Tracking QoS violated events

ABSTRACT

A method in a network node comprises: detecting a Quality of Service (QoS) Violated Event in respect of a particular QoS flow of a Protocol Data Unit (PDU) session; and sending a corresponding QoS violated event report to any one or more of: a Session Management Function (SMF) of the network; a Policy Control Function (PCF) of the network; an Application Function (AF) of the network; and a third party service provider.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/274,769, entitled “TRACKING QOS VIOLATED EVENTS” filed Feb. 13, 2019and claims the benefit of priority to U.S. Provisional Application Ser.No. 62/631,113, filed Feb. 15, 2018, the contents of which are herebyincorporated by reference.

FIELD OF THE INVENTION

The present invention pertains to the field of network management, andin particular to tracking QoS violated events.

BACKGROUND

Ultra-Reliable Low Latency Communications (URLLC) applications, such asindustrial automation control and automated driving vehicles, forexample, require ultra reliable packet delivery. The Third GenerationPartnership Project (3GPP) has developed in Release 15 a new Quality ofService (QoS) model, which includes a delay critical Guaranteed Bit Rate(GBR) QoS resource type. A new QoS parameter, which may be referred toas Maximum Data Burst Volume, has been added for delay critical GBR. QoSflows.

The packets of delay critical GBR QoS flows may belong to applicationsthat are very sensitive to packet delays. For these applications, theviolation of QoS requirements, such as packet delay beyond a particularvalue, may lead to serious issues in the applications in the UserEquipment (UE) side. In order to address issues raised by customer ownedUEs, the network operator may need to refer to records (such as audittrails) of network events.

The current 5G QoS model has a “Notification Control” parameterconfigured by the Policy Control Function (PCF) for a (Radio) AccessNetwork ((R)AN) node to send a notification to the Access and MobilityManagement Function (AMF) when the Guaranteed Flow Bit Rate (GFBR) cannot be supported. This notification does not help to report events inwhich the QoS parameters of delay critical GBR QoS flows are violated.

This background information is provided to reveal information believedby the applicant to be of possible relevance to the present invention.No admission is necessarily intended, nor should be construed, that anyof the preceding information constitutes prior art against the presentinvention.

SUMMARY

An object of embodiments of the present invention is to providetechniques for reporting events in which the QoS parameters of delaycritical GBR QoS flows are violated.

Accordingly, an aspect of the present invention provides a method in anetwork node comprises: detecting a quality of service (QoS) ViolatedEvent in respect of a particular protocol data unit (PDU) session; andsending a corresponding report to a session management function (SMF) ofthe network.

In another broad aspect, a method in a network node is provided,comprising: receiving a configuration indicating how to report a QoSviolated event; detecting a quality of service (QoS) violated event inrespect of a particular QoS flow of protocol data unit (PDU) session;and sending, to a session management function (SMF) of the network, areport corresponding to the detected QoS violated event according to theconfiguration.

In one aspect, the network node comprises one of:

-   a radio access network (RAN) node connected to a user equipment (UE)    associated with the PDU session; and-   a user plane function (UPF) associated with the PDU session.

In another aspect, the method further comprises receiving a policy andcharging control (PCC) rule, wherein the configuration is based on thePCC rule.

In yet another aspect, the method comprises receiving a request toinclude a timestamp associated with a packet delay parameter inaccordance with detected QoS violated event, the timestamp including atleast one of a packet delay and a time that the packet delay isinitiated.

In one variation, detecting the QoS violated event comprises detectingone or more of:

-   a measured packet delay is larger than a predetermined user plane    function (UPF) packet delay budget (PDB);-   a measured data burst volume within a period of the UPF PDB is    larger than a predetermined maximum data burst volume;-   a measured flow bitrate within a predetermined averaging window is    larger than a predetermined maximum flow bit rate (MTBR);-   the UPF cannot support a predetermined guaranteed flow bit rate    (GFBR);-   a measured session-aggregate maximum bit rate (Session-AMBR) is    larger than an authorized session-AMBR; and-   a measured UE-AMBR. is larger than a predetermined subscribed    UE-AMBR,

In yet another aspect, the report comprises one or more of:

-   an event identifier;-   a network Function identifier;-   a user equipment (UE) identifier;-   an application identifier;-   a packet filter;-   a PDU session identifier;-   a QoS flow identifier (QFI);-   a packet delay budget (PDB) indication;-   one or more timestamps;-   a measured packet delay in packet session anchor (PSA) UPF;-   a size of a particular PDU in respect of which the QoS violated    event was detected; and-   a copy of the particular PDU.

In one aspect, sending the report comprises one or more of:

-   sending the report immediately following detection of the QoS    violated event;-   storing one or more reports in a memory, and sending the one or more    reports at a predetermined interval; and-   storing one or more reports in a memory, and sending the one or more    reports in response to a predetermined event.

In one variation, the predetermined event comprises any one or more of:

-   predetermined intervals;-   a user plane (UP) of the PDU session is deactivated;-   the PDU session is released;-   the UE enters a CM-IDLE state; and-   the UE transitions from a CM-CONNECTED state to an RRC-INACTIVE    state.

In one aspect, the configuration is obtained by the SMF uponestablishment or modification of the PDU session.

In another aspect, the method further comprises:

-   receiving, at a policy control function (PCF), the QoS violated    event report;-   receiving, from an application function of the network, a request    for the QoS violated event report; and-   sending, via one of directly and indirectly, the QoS violated event    report to the AF.

In another embodiment, the method further comprises sending the QoSviolated event report via a network exposure function (NEF) of thenetwork.

In a broad aspect, a method comprises obtaining, at a session managementfunction (SMF) from a policy control function (PCF), a configurationindicating how to report a packet delay event, the condition beingassociated with the packet delay parameter which applies to at least oneof a radio access network (RAN) node, a user plane function (UPF), and auser equipment (UE), transmitting, by the SMF to the at least one of theRAN node, the UPF and the UE, the configuration, receiving, by the SMFfrom the at least one of the RAN node, the UPF and the UE, a packetdelay event report generated in accordance with the configuration.

In one variation, the configuration is obtained by the SMF uponestablishment or modification of the PDI; session.

In another variation, the method further comprises requesting the atleast one of the RAN node, the UPF and the UE to include a timestampassociated with the packet delay parameter to at least one protocol dataunit (PDU) during a PDU session between the LE and a network function(NF).

In another aspect, the timestamp specifies at least one of an arrivaltime at, the NF and at the UE, a departure time from the NF and from theUE, and times of arrival and departure at the NF.

In yet another aspect, the packet delay event report including at leastone of a measured packet delay of individual PDUs for quality of service(QoS) flows and an average packet delay of QoS flows for at least one ofan uplink (UL) and a downlink (DL) transmission.

In another variation, the method further comprises receiving a policyand charging control (PCC) rule, the configuration is obtained based onthe PCC rule.

In yet another variation, the method further comprises transmitting, bythe SMF, the packet delay event report to the PCF.

In another aspect, the method further comprises determining, by the SMF,whether a packet delay violation is detected according to the packetdelay event report.

In yet another broad aspect, a network node is provided, comprising:

-   a processor; and-   a memory storing instructions executable in the processor by:-   receiving a configuration indicating how to report a QoS violated    event;-   detecting a quality of service (QoS) violated event in respect of a    particular protocol data unit (PDU) session; and-   sending, to a session management function (SMF) of the network, a    report corresponding to the detected QoS violated even according to    the configuration.

In one aspect, the network node is one of a radio access network (RAN)node connected to a user equipment (UE) associated with the PDU session,and a user plane function (UPF) associated with the PDU session.

In one variation, the network node further comprises instructionsexecutable for receiving a policy and charging control (PCC) rule,wherein the configuration is based on the PCC rule.

In yet another variation, the network node further comprisesinstructions executable for receiving a request to include a timestampassociated with a packet delay parameter in accordance with detected QoSviolated event.

In one aspect, detecting the QoS violated event comprises detecting oneor more of:

-   a measured packet delay is larger than a predetermined user plane    function (UPF) packet delay budget (PDB);-   a measured data burst volume within a period of the UPF PDB is    larger than a predetermined maximum data burst volume:-   a measured flow bitrate within a predetermined averaging window is    larger than a predetermined maximum flow hit rate (MFBR);-   the UPF cannot support a predetermined guaranteed flow bit rate    (GFBR);-   a measured session-aggregate maximum bit rate (Session-AMBR) is    larger than an authorized session-AMBR; and-   a measured UE-AMBR is larger than a predetermined subscribed    UE-AMBR.

In one variation, the report comprises one or more of:

-   an event identifier;-   a network function identifier;-   a user equipment (UE) identifier;-   an application identifier;-   a packet filter;-   a PDU session identifier;-   a QoS flow identifier (QFI);-   a packet delay budget (PDB) indication;-   one or more timestatnps;-   a measured packet delay in packet session anchor (PSA) UPF;-   a size of a particular PDU in respect of which the QoS violated    event was detected; and-   a copy of the particular PDU.

In one aspect, sending the report comprises one or more of:

-   sending the report immediately following detection of the QoS    violated event,-   storing one or more reports in a memory, and sending the one or more    reports at a predetermined interval; and-   storing one or more reports in a memory, and sending the one or more    reports in response to a predetermined event.

In one aspect, the predetermined event comprises any one or more of:

-   predetermined intervals;-   a user plane (UP) of the PDU session is deactivated;-   the PDU session is released;-   the UE enters a CM-IDLE state; and-   the UE transitions from a CM CONNECTED state to an RRC-INACTIVE    state.

In another broad aspect, provided is a session management function (SMF)comprising:

-   a processor; and-   a memory storing instructions executable in the processor by:-   obtaining, from a policy control function (PCF), a configuration    indicating how to report a packet delay event, the condition being    associated with the packet delay parameter which applies to at least    one of a radio access network (RAN) node, a user plane function    (UPF), and a user equipment (UE);-   transmitting, to the at least one of the RAN node, the UPF and the    UE, the configuration; and-   receiving, from the at least one of the RAN node, the UPF and the    UE, a packet delay event report generated in accordance with the    configuration.

In one aspect, the configuration is obtained by the SMF uponestablishment or modification of the PDU session.

In another aspect, the function further comprises instructionsexecutable for requesting the at least one of the RAN node, the UPF andthe UE to include a timestamp associated with the packet delay parameterto at least one protocol data unit (PDU) during a PDU session betweenthe UE and a network function (NF).

In one variation, the timestamp specifies at least one of an arrivaltime at the NF and at the UE, a departure time from the NF and from theUE, and times of arrival and departure at the

In another variation, the packet delay event report includes at leastone of a measured packet delay of individual PDUs for quality of service(QoS) flows and an average packet delay of QoS flows for at least one ofan uplink (UL) and a downlink (DL) transmission.

In one aspect, the instructions are executable for receiving a policyand charging control (PCC) rule, the configuration is obtained based onthe PCC rule.

In another aspect, the instructions are executable for transmitting thepacket delay event report to the PCF.

In a further aspect, the instructions are executable for determiningwhether a packet delay violation is detected according to the packetdelay event report.

Provided, in another broad aspect, is a method comprising:

-   receiving, at a user plane function (UPF) during a protocol data    unit (PDU) session, a packet destined for a user equipment (UE); and-   encapsulating the packet to include a first timestamp indicating a    time of arrival of the packet at the UPF.

In one variation, the method further comprises encapsulating the packetto further include a second timestamp indicating a time transmission ofthe packet from the UPF.

In one aspect, the UPF is a first UPF in a plurality of UPFs of thenetwork, and the method further comprises:

-   calculating an accumulation of timestamps based on the a first and    the second timestamps of each of the plurality of UPFs; and-   determining occurrence of a QoS violation event based on the    accumulation of timestamps.

In one variation, the timestamp is carried by one of: a field of a GTP-Uprotocol, and an Extension Header field of a GTP-U protocol having aNext Extension Header Type that indicates a new timestamp type.

Also provided, in a broad aspect, is a network node comprising

-   a processor; and-   a memory storing instructions executable in the processor by:-   receiving during a protocol data unit (PDU) session, a packet    destined for a user equipment (UE); and-   encapsulating the packet to include a first timestamp indicating a    time of arrival of the packet at the network node.

In one variation, the instructions are further executable to encapsulatethe packet to further include a second timestamp indicating a timetransmission of the packet from the network node.

In one variation, the network node is a first network node in aplurality of network nodes of the network, and the instructions arefurther executable to:

-   calculate an accumulation of timestamps based on the a first and the    second timestamps of each of the plurality of network nodes; and-   determine occurrence of a QoS violation event based on the    accumulation of timestamps,

In one variation, the timestamp is carried by one of: a field of a GTP-Uprotocol, and an Extension Header field of a GTP-U protocol having aNext Extension Header Type that indicates a new timestamp type.

In another variation, the network node is a user plane function (UPF).

Also provided, in a broad aspect, is a non-transitory computer-readablemedia storing computer instructions, that when executed by one or moreprocessors, cause the one or more processors to perform any of thepreceding methods.

In another broad aspect, provided is a communication system comprisingat least one of a network node configured to perform selected ones ofthe preceding methods, a session management function (SMF) configured toperform selected ones of the preceding methods, and a network nodeconfigured to perform selected ones of the preceding methods.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages of the present invention will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1 is a block diagram of an electronic device within a computing andcommunications environment that may be used for implementing devices andmethods in accordance with representative embodiments of the presentinvention;

FIG. 2 is a block diagram illustrating a logical platform under which anElectronic Device can provide virtualization services;

FIG. 3 is a block diagram illustrating a service-based view of a systemarchitecture of a 5G Core Network;

FIG. 4 is a message flow diagram illustrating a representative processin accordance with embodiments of the present invention;

FIG. 5 is a block diagram schematically illustrating a representativeformat of packets sent in N3 and N9 interfaces, which may be used inembodiments of the present invention;

FIG. 6 is a block diagram schematically illustrating a representativeformat of the N3/N9 Encapsulation header of FIG. 5 , in accordance withrepresentative embodiments of the present invention;

FIG. 7 is a block diagram schematically illustrating an example networkUser Plane, which may be used in embodiments of the present invention;

FIG. 8 is a block diagram schematically illustrating anotherrepresentative format of the N3/N9 Encapsulation header of FIG. 5 ,which may be used in embodiments of the present invention;

FIGS. 9A-9B show a message flow diagram illustrating a representativeprocess for UE-requested PDU Session Establishment for non-roaming androaming with local breakout, which may be used in embodiments of thepresent invention;

FIGS. 10A-10C show a message flow diagram illustrating a representativeprocess for UE-requested PDU Session Establishment for home-routedroaming scenarios, which may be used in embodiments of the presentinvention;

FIGS. 11A-11B show a message flow diagram illustrating a representativeprocess for UE or network requested PDU Session Modification procedure(non-roaming and roaming with local breakout), which may be used inembodiments of the present invention;

FIG. 12 is a message flow diagram illustrating a representative N4reporting procedure, which may be used in embodiments of the presentinvention.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

In the following description, features of the present invention aredescribed by way of example embodiments. For convenience of description,these embodiments make use of features and terminology known fromcommunication system specifications, such as 4G and 5G networks, asdefined by the Third Generation Partnership Project (3GPP). However, itmay be understood that the present invention is not limited to suchnetworks.

In the following description, the term “QoS violated event” is used torefer to an event in which one or more parameters of a QoS agreementhave been violated. Embodiments of the present invention are agnosticwith respect to the cause of a QoS violated event. For example, a QoSviolated event may be caused by the network (e.g. due to a lack ofavailable capacity at a particular time) or by a client (e.g. due to anapplication transmitting an excessively large amount of data in a giventime period). The mobile network operators may detect the QoS violatedevents in order to identify the network functions or network segmentsthat cause the QoS violation so that suitable remedy solutions can beimplemented. The mobile network operator may also re-negotiate with theclient to change the QoS agreements.

FIG. 1 is a block diagram of an electronic device (ED) 102 illustratedwithin a computing and communications environment 100 that may be usedfor implementing the devices and methods disclosed herein. In someembodiments, the electronic device 102 may be an element ofcommunications network infrastructure, such as a base station (forexample a NodeB, enhanced Node B (eNodeB), a next generation NodeB(sometimes referred to as a gNodeB or gNB)), a home subscriber server(HSS), a gateway (GW) such as a packet gateway (PGW) or a servinggateway (SGW) or various other nodes or functions within an evolvedpacket core (EPC) network. In other embodiments, the electronic device102 may be a device that connects to network infrastructure over a radiointerface, such as a mobile phone, smart phone or other such device thatmay be classified as a User Equipment (UE). In some embodiments, ED 102may be a Machine Type Communications (MTC) device (also referred to as amachine-to-machine (m2m) device), or another such device that may becategorized as a UE despite not providing a direct service to a user. Insome references, an ED 102 may also be referred to as a mobile device(MD), a term intended to reflect devices that connect to mobile network,regardless of whether the device itself is designed for, or capable of,mobility. Specific devices may utilize all of the components shown oronly a subset of the components, and levels of integration may vary fromdevice to device. Furthermore, a device may contain multiple instancesof a component, such as multiple processors, memories, transmitters,receivers, etc. The electronic device 102 typically includes a processor106, such as a Central Processing Unit (CPU), and may further includespecialized processors such as a Graphics Processing Unit (GPU) or othersuch processor, a memory 108, a network interface 110 and a bus 112 toconnect the components of ED 102. ED 102 may optionally also includecomponents such as a mass storage device 114, a video adapter 116, andan I/O interface 118 (shown in dashed lines).

The memory 108 may comprise any type of non-transitory system memory,readable by the processor 106, such as static random-access memory(SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM),read-only memory (ROM), or a combination thereof. In specificembodiments, the memory 108 may include more than one type of memory,such as ROM for use at hoot-up, and DRAM for program and data storagefor use while executing programs. The bus 112 may be one or more of anytype of several bus architectures including a memory bus or memorycontroller, a peripheral bus, or a video bus.

The electronic device 102 may also include one or more networkinterfaces 110, which may include at least one of a wired networkinterface and a wireless network interface. As illustrated in FIG. 1 ,network interface 110 may include a wired network interface to connectto a network 120, and also may include a radio access network interface122 for connecting to other devices over a radio link. When ED 102 isnetwork infrastructure, the radio access network interface 122 may beomitted for nodes or functions acting as elements of the Core Network(CN) other than those at the radio edge (e.g. an eNB). When ED 102 isinfrastructure at the radio edge of a network, both wired and wirelessnetwork interfaces may be included, When ED 102 is a wirelesslyconnected device, such as a User Equipment, radio access networkinterface 122 may be present and it may be supplemented by otherwireless interfaces such as Wifi network interfaces. The networkinterfaces 110 allow the electronic device 102 to communicate withremote entities such as those connected to network 120.

The mass storage 114 may comprise any type of non-transitory storagedevice configured to store data, programs, and other information and tomake the data, programs, and other information accessible via the bus112, The mass storage 114 may comprise, for example, one or more of asolid-state drive, hard disk drive, a magnetic disk drive, or an opticaldisk drive. In some embodiments, mass storage 114 may be remote to theelectronic device 102 and accessible through use of a network interfacesuch as interface 110. In the illustrated embodiment, mass storage 114is distinct from memory 108 where it is included, and may generallyperform storage tasks compatible with higher latency, but may generallyprovide lesser or no volatility. In some embodiments, mass storage 114may be integrated with a memory 108 to form an heterogeneous memory.

The optional video adapter 116 and the I/O interface 118 (shown indashed lines) provide interfaces to couple the electronic device 102 toexternal input and output devices. Examples of input and output devicesinclude a display 124 coupled to the video adapter 116 and an 110 device126 such as a touch-screen coupled to the I/O interface 118. Otherdevices may be coupled to the electronic device 102, and additional orfewer interfaces may be utilized. For example, a serial interface suchas Universal Serial Bus (USB) (not shown) may be used to provide aninterface for an external device. Those skilled in the art willappreciate that in embodiments in which ED 102 is part of a data center,I/O interface 118 and Video Adapter 116 may be virtualized and providedthrough network interface 110.

In some embodiments, electronic device 102 may be a standalone device,while in other embodiments electronic device 102 may be resident withina data center. A data center, as will be understood in the art, is acollection of computing resources (typically in the form of servers)that can be used as a collective computing and storage resource. Withina data center, a plurality of servers can be connected together toprovide a computing resource pool upon which virtualized entities can beinstantiated. Data centers can be interconnected with each other to formnetworks consisting of pools computing and storage resources connectedto each by connectivity resources. The connectivity resources may takethe form of physical connections such as Ethernet or opticalcommunications links, and may include wireless communication channels aswell, If two different data centers are connected by a plurality ofdifferent communication channels, the links can be combined togetherusing any of a number of techniques including the formation of linkaggregation groups (LAGs). It should be understood that any or all ofthe computing, storage and connectivity resources (along with otherresources within the network) can be divided between differentsub-networks, in some cases in the form of a resource slice. If theresources across a number of connected data centers or other collectionof nodes are sliced, different network slices can be created.

FIG. 2 is a block diagram schematically illustrating an architecture ofa representative server 200 usable in embodiments of the presentinvention. It is contemplated that the server 200 may be physicallyimplemented as one or more computers, storage devices and routers (anyor all of which may be constructed in accordance with the system 100described above with reference to FIG. 1 ) interconnected together toform a local network or cluster, and executing suitable software toperform its intended functions. Those of ordinary skill will recognizethat there are many suitable combinations of hardware and software thatmay be used for the purposes of the present invention, which are eitherknown in the art or may be developed in the future. For this reason, afigure showing the physical server hardware is not included in thisspecification. Rather, the block diagram of FIG. 2 shows arepresentative functional architecture of a server 200, it beingunderstood that this functional architecture may be implemented usingany suitable combination of hardware and software. It will also beunderstood that server 200 may itself be a virtualized entity. Because avirtualized entity has the same properties as a physical entity from theperspective of another node, both virtualized and physical computingplatforms may serve as the underlying resource upon which virtualizedfunctions are instantiated.

As may be seen in FIG. 2 , the illustrated server 200 generallycomprises a hosting infrastructure 202 and an application platform 204.The hosting infrastructure 202 comprises the physical hardware resources206 (such as, for example, information processing, traffic forwardingand data storage resources) of the server 200, and a virtualizationlayer 208 that presents an abstraction of the hardware resources 206 tothe Application Platform 204. The specific details of this abstractionwill depend on the requirements of the applications being hosted by theApplication layer (described below). Thus, for example, an applicationthat provides traffic forwarding functions may be presented with anabstraction of the hardware resources 206 that simplifies theimplementation of traffic forwarding policies in one or more routers.Similarly, an application that provides data storage functions may bepresented with an abstraction of the hardware resources 206 thatfacilitates the storage and retrieval of data (for example usingLightweight Directory Access Protocol—LDAP). The virtualization layer208 and the application platform 204 may be collectively referred to asa Hypervisor.

The application platform 204 provides the capabilities for hostingapplications and includes a virtualization manager 210 and applicationplatform services 212. The virtualization manager 210 supports aflexible and efficient multi-tenancy run-time and hosting environmentfor applications 214 by providing Infrastructure as a Service (IaaS)facilities. In operation, the virtualization manager 210 may provide asecurity and resource “sandbox” for each application being hosted by theplatform 204. Each “sandbox” may be implemented as a Virtual Machine(VM) 216 that may include an appropriate operating system and controlledaccess to (virtualized) hardware resources 206 of the server 200. Theapplication-platform services 212 provide a set of middlewareapplication services and infrastructure services to the applications 214hosted on the application platform 204, as will be described in greaterdetail below.

Applications 214 from vendors, service providers, and third-parties maybe deployed and executed within a respective Virtual Machine 216. Forexample, MANagement and Orchestration (MANO) functions and ServiceOriented Network Auto-Creation (SONAC) functions (or any of SoftwareDefined Networking (SDN), Software Defined Topology (SDT), SoftwareDefined Protocol (SDP) and Software Defined Resource Allocation (SDRA)controllers that may in some embodiments be incorporated into a SONACcontroller) may be implemented by means of one or more applications 214hosted on the application platform 204 as described above. Communicationbetween applications 214 and services in the server 200 may convenientlybe designed according to the principles of Service-Oriented Architecture(SOA) known in the art.

Communication services 218 may allow applications 214 hosted on a singleserver 200 to communicate with the application-platform services 212(through pre-defined Application Programming interfaces (APIs) forexample) and with each other (for example through a service-specificAPI).

A service registry 220 may provide visibility of the services availableon the server 200. In addition, the service registry 220 may presentservice availability (e.g. status of the service) together with therelated interfaces and versions. This may be used by applications 214 todiscover and locate the end-points for the services they require, and topublish their own service end-point for other applications to use.

Mobile-edge Computing allows cloud application services to be hostedalongside virtualized mobile network elements in data centers that areused for supporting the processing requirements of the Cloud-RadioAccess Network (C-RAN). For example, eNodeB or gNB nodes may bevirtualized as applications 214 executing in a VM 216. Networkinformation Services (NIS) 222 may provide applications 214 withlow-level network information. For example, the information provided byNIS 222 may be used by an application 214 to calculate and presenthigh-level and meaningful data such as: cell-ID, location of thesubscriber, cell load and throughput guidance.

A Traffic Off-Load Function (TOF) service 224 may prioritize traffic,and route selected, policy-based, user-data streams to and fromapplications 214. The TOF service 224 may be supplied to applications214 in various ways, including: A Pass-through mode where (either orboth of uplink and downlink) traffic is passed to an application 214which can monitor, modify or shape it and then send it back to theoriginal Packet Data Network (PDN) connection (e.g. 3GPP bearer); and anEnd-point mode where the traffic is terminated by the application 214which acts as a server.

As may be appreciated, the server architecture of FIG. 2 is an exampleof Platform Virtualization, in which each Virtual Machine 216 emulates aphysical computer with its own operating system, and (virtualized)hardware resources of its host system. Software applications 214executed on a virtual machine 216 are separated from the underlyinghardware resources 206 (for example by the virtualization layer 208 andApplication Platform 204). In general terms, a Virtual Machine 216 isinstantiated as a client of a hypervisor (such as the virtualizationlayer 208 and application-platform 204) which presents an abstraction ofthe hardware resources 206 to the Virtual Machine 216.

Other virtualization technologies are known or may be developed in thefuture that may use a different functional architecture of the server200. For example, Operating-System-Level virtualization is avirtualization technology in which the kernel of an operating systemallows the existence of multiple isolated user-space instances, insteadof just one. Such instances, which are sometimes called containers,virtualization engines (VEs) or jails (such as a “FreeBSD jail” or“chroot jail”), may emulate physical computers from the point of view ofapplications running in them. However, unlike virtual machines, eachuser space instance may directly access the hardware resources 206 ofthe host system, using the host systems kernel. In this arrangement, atleast the virtualization layer 208 of FIG. 2 would not be needed by auser space instance. More broadly, it will be recognised that thefunctional architecture of a server 200 may vary depending on the choiceof virtualisation technology and possibly different vendors of aspecific virtualisation technology.

FIG. 3 illustrates a service-based architecture 300 for a 5G or NextGeneration Core Network (5GCN/NGCN/NCN). This illustration depictslogical connections between nodes and functions, and its illustratedconnections should not be interpreted as direct physical connections. ED102 forms a radio access network connection with a (Radio) AccessNetwork ((R)AN) node 302 (which may, for example, be an gNodeB (gNB)),which is connected to a User Plane (UP) Function (UPF) 304 such as a UPGateway over a network interface providing a defined interface such asan N3 interface. UPF 304 provides a logical connection to a Data Network(DN) 306 over a network interface such as an N6 interface. The radioaccess network connection between the ED 102 and the (R)AN node 302 maybe referred to as a Data Radio Bearer (DRB).

DN 306 may be a data network used to provide an operator service, or itmay be outside the scope of the standardization of the Third GenerationPartnership Project (3GPP), such as the Internet, a network used toprovide third party service, and in some embodiments DN 306 mayrepresent an Edge Computing network or resource, such as a Mobile EdgeComputing (MEC) network.

ED 102 also connects to the Access and Mobility Management Function(AMF) 308 through a logical N1 connection (although the physical path ofthe connection is not direct). The AMF 308 is responsible forauthentication and authorization of access requests, as well as mobilitymanagement functions. The AMF 308 may perform other roles and functionsas defined by the 3GPP Technical Specification (TS) 23.501. In a servicebased view, AMF 308 can communicate with other core network controlplane functions through a service based interface denoted as Namf.

The Session Management Function (SMF) 310 is a network function that isresponsible for the allocation and management of IP addresses that areassigned to a UE as well as the selection of a UPF 304 (or a particularinstance of a UPF 304) for traffic associated with a particular sessionof ED 102, The SMF 310 can communicate with other core networkfunctions, in a service based view, through a service based interfacedenoted as Nsmf. The SME 310 may also connect to a UPF 304 through alogical interface such as network interface N4.

The Authentication Server Function (AUSF) 312, provides authenticationservices to other network functions over a service based Nausfinterface.

A Network Exposure Function (NEF) 314 can be deployed in the network toallow servers, functions and other entities such as those outside atrusted domain to have exposure to services and capabilities within thenetwork. In one such example, an NEF 314 can act much like a proxybetween an application server outside the illustrated network andnetwork functions such as the Policy Control Function (PCF) 316, the SMF310, the UDM 320, and the AMF 308, so that the external applicationserver can provide information that may be of use in the setup of theparameters associated with a data session, The NEF 314 can communicatewith other network functions through a service based Nnef networkinterface, The NEF 314 may also have an interface to non-3GPP functions.

A Network Repository Function (NRF) 318, provides network servicediscovery functionality. The NRF 318 may be specific to the Public LandMobility Network (PLMN) or network operator, with which it isassociated. The service discovery functionality can allow networkfunctions and UEs connected to the network to determine where and how toaccess existing network functions, and may present the service basedinterface Nnrf.

PCF 316 communicates with other network functions over a service basedNpcf interface, and can be used to provide Policy and Charging Control(PCC) functionality to other network functions, including those withinthe control plane. The PCC functionality may include: a Policy andCharging Rules Function (PCRF); a Policy and Charging EnforcementFunction (PCEF); and a Bearer Binding and Event Reporting Function(BBERF). Implementation of PCC functionality is not necessarily theresponsibility of the PCF 316, but rather is typically theresponsibility of network functions to which the PCF 316 transmitsapplicable PCC rules. In one such example the PCF 316 may transmit a PCCrule (associated with a policy) associated with session management tothe SMF 310, which may use the received PCC rule to implement theassociated policy. This arrangement may be used to enable a unifiedpolicy framework within which network behavior can be governed.

A Unified. Data Management Function (UDM) 320 can present a servicebased Nudm interface to communicate with other network functions, andcan provide data storage facilities to other network functions. Unifieddata storage can allow for a consolidated view of network informationthat can be used to ensure that the most relevant information can bemade available to different network functions from a single resource.This can make implementation of other network functions easier, as theydo not need to determine where a particular type of data is stored inthe network. The UDM 320 may employ an interface Nudr to connect to aUser Data Repository (UDR). The PCF 316 may be associated with the UDM320 because it may be involved with requesting and providingsubscription policy information to the UDR, but it should be understoodthat typically the PCF 316 and the UDM 320 are independent functions.

The PCF 316 may have a direct interface to the UDR. The UDM 320 canreceive requests to retrieve content stored in the UDR 340, or requeststo store content in the UDR 340. The UDM 320 is typically responsiblefor functionality such as the processing of credentials, locationmanagement and subscription management. The UDR 340 may also support anyor all of Authentication Credential Processing, User Identificationhandling, Access Authorization, Registration/Mobility management,subscription management, and Short Message Service (SMS) management. TheUDR is typically responsible for storing data provided by the UDM 320.The stored data is typically associated with policy profile information(which may be provided by PCF 316) that governs the access rights to thestored data. In some embodiments, the UDR may store policy data, as wellas user subscription data which may include any or all of subscriptionidentifiers, security credentials, access and mobility relatedsubscription data. and session related data.

Application Function (AF) 322 represents the non-data plane (alsoreferred to as the non-user plane) functionality of an applicationdeployed within a network operator domain and within a 3GPP compliantnetwork. The AF 322 interacts with other core network functions througha service based Naf interface, and may access network capabilityexposure information, as well as provide application information for usein decisions such as traffic routing. The AF 322 can also interact withfunctions such as the PCF 316 to provide application specific input intopolicy and policy enforcement decisions. It should be understood that inmany situations the AF 322. does not provide network services to otherNFs, and instead is often viewed as a consumer or user of servicesprovided by other NFs. An application outside the 3GPP network, canperform many of the same functions as AF 322 through the use of NEF 314.

ED 102 communicates with network functions that are in the User Plane(UP) 324, and the Control Plane (CP) 326. The UPF 304 is a part of theCN UP 324 (DN 306 being outside the 5GCN). (R)AN node 302 may beconsidered as a part of a User Plane, but because it is not strictly apart of the CN, it is not considered to be a part of the CN UP 324. ANTE308, SMF 310, AUSF 312, NEF 314, NRF 318, PCF 316, and UDM 320 arefunctions that reside within the CN CP 326, and are often referred to asControl Plane Functions. AF 322 may communicate with other functionswithin CN CP 326 (either directly or indirectly through the NEF 314),but is typically not considered to be a part of the CN CP 326.

Those skilled in the art will appreciate that there may be a pluralityof UPFs connected in seines between the (R)AN node 302 and the DN 306.and multiple data sessions to different DNs can be accommodated throughthe use of multiple UPFs in parallel.

User Plane (UP) packets flows to and from a particular ED 102, UPpackets are normally routed between the (R)AN node 302 connected to theED 102, and the DN 306 using General Packet Radio Service (GPRS)Tunneling Protocol for user plane (GTP-U) tunnels 328 and possiblyIP-based tunnel 330 established through the N3 and N6 interfaces,respectively. In some examples, connections between (R)AN node 302 and aUPF 304 would make use of GTP-U tunnel 328. Connections between theillustrated UPF 304 and other unillustrated UPFs would also make sure ofa GTP-U tunnel. Upon leaving the CN UP, a packet may make use of anInternet Protocol (IP)-based connection between the LW and the DN 306instead of a GTP-U tunnel, especially if DN 306 is outside the domain ofthe operator. Optionally, a GTP-U tunnel 328 may be established betweenthe (R)AN node 302 and the UPF 304 for each Radio Bearer between the ED102 and the (R)AN node 302, which might allow for a one-to-onerelationship between Radio Bearers and GTP-U tunnels. Where there is asecond UPF, there would usually be a corresponding GTP-U tunnel betweenthe UPFs for each GTP-U tunnel between the (R)AN node 302 and the UPF304. This results in each radio bearer being associated with a set ofGTP-U tunnels forming a path through the CN UP. Each GTP-U tunnel maysupport multiple PDU sessions, and packet flows with multiple differentQoS requirements. Packet flows within a GIP-1U tunnel, such as tunnel328, having the same QoS requirements may be grouped together as a QoSFlow, which may be identified by a given QFI. The QFI can therefore beused for queuing and prioritization of packet forwarding through theGTP-U tunnels 328 and 330.

At the time of PDU session establishment, the SMF 310 typically providesone or more QoS Profiles to the (R)AN node 302. These QoS Profilescontain QoS parameters for controlling the forwarding of packets havingvarious QoS requirements. Example QoS parameters that may be included ina QoS Profile may include: 5G QoS Identifier (5QI), Allocation andRetention Priority (ARP), Reflective QoS Attribute (RCM), GuaranteedFlow Bit Rate (GFBR), Maximum Flow Bit Rate (MFBR), and NotificationControl parameters.

At the time of PDU session establishment, the SMF 310 typically providesone or more QoS Rules to the ED 102. These QoS Rules contain informationfor controlling the forwarding of packets having various QoSrequirements. Example information that may be included in a QoS Rule mayinclude: QoS Flow Identifier (QFI), one or more packet filters andprecedence values, and QoS parameters (such as 5G QoS Identifier (5QI),Guaranteed Bit Rate (GBR), Maximum Bit Rate (MBR), etc.). Duringrun-time, the ED 102 may insert the QFI into UpLink (UL) packets priorto sending them through the RB, such as data radio bearer (DRB), to the(R)AN node 302. Upon receipt of the LTL packet from the ED 102, the(R)AN node 302. may use the QFI of the packet and the QoS Profiles tocontrol queueing and transmission of the packet to the UPF 304.

As may be appreciated, there can be more than one QoS rule associatedwith a given QoS Flow. These QoS rules may contain the same QFI. In somecases, a Default QoS rule may be defined. The Default. QoS rule may bethe only QoS rule of a PDU session that does not contain a packetfilter.

Embodiments of the present invention provide techniques for reportingQoS violated events pertaining to a particular PDU session, for examplefor a URLLC application. An objective is to enable the PCF 316 toprovide QoS monitoring and QoS violated event reporting policy to the(R)AN 302 and UPF 304 for delay critical GBR QoS Flows, for example.

Since the QoS violated event reporting requires QoS monitoring, in thepresent document the phrase “QoS monitoring and QoS violated eventreporting” may be also referred to as “QoS violated event reporting” forshort. However, the QoS monitoring and QoS violated event reportingpolicy may require the QoS monitoring function in the network entitiessuch as (R)AN UPF, and UE to report the measured QoS parameters, eitherwhen the QoS parameters are violated or not violated.

Referring to FIG. 4 , in some embodiments, the SMF 310 may be configuredwith QoS violated event reporting functionality by means of a PCC ruleprovided by the PCF 316. For example, during the establishment of a PI)Usession, or during a PCC rule modification process, the PCF 316 may senda QoS Notification Control (QNC) message containing a PCC rule relatingto QoS violated event Reporting (QVER) to the SMF 310. If the PCC rulerequires QoS violated event Reporting, the SMF 310 may forward a QoSviolated event reporting request to the (R)AN 302 and/or UPF 304. Ifeither of the (R)AN 302 or the UPF 304 subsequently detect aQoS-Violated Event, the monitoring function in the (R)AN 302 or in theUPF 304 may send a corresponding QoS violated event report to the SMF310. The SMF 310 may collect received QoS violated event reports andsend them to the PCF 316. The PCF 316 may store received. QoS violatedevent reports in a charging system, such as an Online Charging System(OCS) or an Offline Charging System (OFCS). Alternatively, the PCF 316may store received QoS violated event reports in another storagefunction, such as the UDR 340, for example, The online and/or offlinecharging system may use the QoS violated event reports to adjust thecharging policy, such as reducing the charge rate for the services orUEs that have QoS violated events. The Network Data Analytics Function(NWDAF) may subscribe PCF and/or SMF for QoS violated events to analyzethe network performance, such as QoS performance, QoS profile(s) fortraffic types or service types, which is represented by Application ID.

In some embodiments, one or more of the QoS violated event reports maybe sent to an Application Function (AF) 322 associated with theapplication. Either the SMF 310 or the PCF 316 may send QoS violatedevent reports to the AF 322, either directly or indirectly via the NEF314.

The AF 322 may send a subscription request for the QoS violated eventreports to the PCF 316 or SMF 310, either directly or via the NEF 314.Such a subscription request may have a conventional format, and may betreated by the receiving function (i.e. either the PCF 316 or SMF 310)in a conventional manner, except that the content of the request isconfigured to cause the receiving function to send QoS violated eventreports to the AF 322. When the PCF 316 receives the subscriptionrequest for QoS-Violated Event reports, the PCF 316 may trigger a PCCupdate process, and consequently send a QNC message containing a PCCrule that includes the QoS violated event Reporting indication to theSMF 310. The SMF 310 may then configure the (R)AN 302 and UPF 304 tomonitor and report QoS violated events to the PCF 316 and/or the AF 322.The AF subscription request may include one or more of followinginformation: the QoS parameters) to be monitored (such as packet delay,actual bit rate of QoS flow) the QoS violated events to be monitored,the information to identify the QoS flow (such as IP packet filter,Ethernet packet filter, IP or Ethernet address of the UE used for theQoS flow), how often the QoS report is sent to the AF (e.g. immediatelyafter the QoS event happens, or periodically, or other events such aswhen the PDU session released, or when the UE entered CM-IDLE), theperiodicity of QoS reports, address(es) of the AF that receives the QoSreport. The address(es) of the AF that receive the QoS report could bethe same and/or different with the address of the AF that sends the QoSsubscription request. The address of the AF could be an IP packet filter(which may include IP address and/or TCP or UDP port of the AF), or anAF identifier (such as AF-Service-Identifier).

In some embodiments, QoS violated events may include:

-   -   a measured bit rate of the PDU session is higher than the        Maximum Bit Rate (MBR) parameter defined in a QoS agreement, for        example. The bit rate may be measured at any one or more of the        UE, a (R)AN node 302, and a UPF 304 traversed by packets        associated with the PDU session. For non-GBR QoS flows, the MBR        may be a Session Aggregate Maximum Bit Rate (AMBR) or a UE-AMBR,        or a MBR of a QoS flow of the PDU session. for GBR flows, the        MBR may be a Maximum Flow Bit Rate (MFBR) defined in a QoS        agreement, for example;    -   a measured data burst volume within a predefined (R)AN Packet        Delay Budget ((R)AN-PDB) is larger than a predefined Maximum        Data Burst Volume of a QoS flow;    -   a measured packet delay incurred by a PDU of the PDU session at        a (R)AN node is larger than the predefined (R)AN-PDB of a QoS        flow;    -   a measured packet delay incurred by a PDU of the PDU session at        a UPF is larger than the predefined PDB for the UPF of a QoS        flow;    -   a measured end-to-end packet delay incurred by a PDU of the PDU        session measured at a UPF or (R)AN node is larger than the        predefined PDB for this QoS flow;    -   a PDU is dropped in a network function (NF), such as (R)AN and        UPF;    -   a measured packet error rate (PER) of a QoS flow of the PDU        session is higher than a predefined maximum PER given in a        corresponding QoS profile for the QoS flow at the (R)AN node; or        a QoS rule at the UE; or a QoS policy at the UPF;    -   a QoS flow is released due to a lack of network resources;

The above-noted QoS violated events may happen in either the uplink (UL)or downlink (DL) direction. The QoS flow could be GBR QoS flow, delaycritical GBR QoS flow, or non-GBR QoS flow, or other types of QoS flows.

In some embodiments, the SMF may send the QoS violated event reportingrequest only to the (R)AN 302. When the (R)AN 302 receives a QoSviolated event reporting request, for example. the (R)AN 302 maysubsequently report QoS violated events to the PCF 316 and/or the AF322, such as

-   -   a measured packet delay of a PDU of a QoS flow received at a 5G        access node (5G-AN) is larger than the predefined PDB of the        5G-AN for this QoS flow;    -   a measured data burst volume of a QoS flow within a period of        the predefined PDB of the 5G-AN is larger than a predefined        Maximum Data Burst Volume for this QoS flow; and    -   a measured flow bitrate of a QoS flow within a predefined        Averaging Window for this QoS flow is larger than the MFBR        defined for this QoS flow, for example,    -   and some other QoS violated events described earlier.

In some embodiments, the (R)AN 302 may send a QNC notification messagecontaining a QoS violated event Report towards the SMF 310. The QNCnotification message may include any one or more of a time stamp of theevent; (R)AN ID (e.g. IP Address); UE ID (e.g. SUPI, GPSI); PDU SessionID; QFI; the name of violated QoS parameter, and the measured value ofviolated QoS parameter. If the packet delay is larger than the 5G-ANPDB, the notification may additionally include the packet size.

The SMF 310 may be configured by the PCF 316 to control how often QoSviolated event reports from the (R)AN 302 are forwarded to the PCF 316,for example: immediately; periodically; event-based, such as when the UPof the PDU Session is deactivated, when the UE enters CM-IDLE state, orwhen the PDU Session is released. The PCF may provide the periodicity ofQoS violated event reports in a PCC rule to the SMF.

A technical benefit of the above-described embodiment is that it enablesthe SMF to configure the (R)AN 302, in an embodiment as illustrated atStep 2 b, to report QoS violated events for delay critical QoS flows.

The above description focusses on configuring the (R)AN 302 to implementQoS-Violated Event reporting functionality. As may be appreciated, asimilar approach may be used to implement QoS violated event reportingfunctionality in the UPF 304. For example, in the embodiment illustratedin FIG. 4 , at Step 1, the PCF 316 may send a QoS Notification Control(QNC) message containing an applicable QoS violated event Reporting(QVER) PCC rule to the SMF 310. In some embodiments, the QVER PCC rulemay have a format closely similar to that used for conventional PCCRules, except that it may include a “QoS violated event report”parameter, which indicates whether QoS violated events should bereported when one or more QoS parameters are violated.

If the QVER PCC rule requires QoS violated event Reporting, the SMF 310,at Step 2 a, may forward a QoS violated event reporting request to theUPF 304.

The Policy and Charging Enforcement Function (PCEF) in the UPF can beconfigured in accordance with the QVER PCC rule to report QoS violatedevents. For delay critical GBR Flows, if configured, the PCEF may send,at Step 4 a, a QoS violated event notification to the SMF 310 for anydetected QoS violated events detected at UPF 3 a and (R)AN 3 b, inaccordance with Steps 4 a, 4 b respectively, including the followingevents, for example:

-   -   A measured packet delay of a PDU of a QoS flow received at the        UPF is longer than the predefined PDB of the UPF for this QoS        flow.    -   The measured flow bitrate of a particular QoS flow is larger        than a predefined maximum flow bit rate (MFBR) for this QoS        flow.    -   The measured data burst volume of a particular QoS flow within a        period of the PDB of the UPF is larger than a predefined Maximum        Data Burst Volume for this QoS flow;    -   And some other QoS violated events described above.

The QoS violated event report contained in a QNC notification messagesent towards the SMF 310 by the UPF may include any one or more of: atime stamp of the event; a UPF ID (e.g. IP Address); UE ID (e.g. SUPI,GPSI); PDU Session ID; QFI; the name of violated QoS parameter; and themeasured value of violated QoS parameter. If the packet delay is largerthan the UPF PDB, the QoS violated event notification may additionallyinclude the packet size.

In some embodiments, a PCC rule may include a “QoS Notification Control(QNC)” parameter, which indicates whether notifications are requestedfrom a 3GPP (R)AN when the GFBR can no longer (or again) be fulfilledfor a. QoS Flow during the lifetime of the QoS Flow. In someembodiments, the conventional (R)AN notification message format may beextended to include one or more fields for QoS violated event reportspertaining to delay critical QoS flows. Such embodiments may also coveradditional solutions such as:

-   -   QoS violated event reporting for any QoS flows, rather than just        delay critical GBR flows.    -   The QNC parameter in PCC rule can be used to instruct the SMF to        request the UPF and/or the UE to report the QoS violated events.        This arrangement may obviate the need for an additional “QoS        violated event report” parameter in PCC rules for configuring CN        functions (such as UPF and SMF) to implement the QoS violated        event report functionality.

In the foregoing description, QoS violated event reports can be sentfrom (R)AN 302 to SMF 310 at Step 4 b, from UPF 304 to SMF 310 at Step 4a, from SMF 310 to PCF 316 at Step 5, from SMF 310 to AF 322, from PCF316 to AF 322. The communications between SMF 310 (or PCF 316) and AF322 could be transfer by the NEF 314. In some embodiments, QoS violatedevent report traffic may be transmitted according to any one or more ofthe following methods:

-   -   Immediately: the QoS violated event report is sent by the        detecting function (i.e. either the (R)AN or the UPF)        immediately after the event is detected 3 a, 3 h, or is sent by        a receiving function (e.g. the SMF at Step 5 or PCF) immediately        after it is received.    -   Periodically: the QoS violated event reports are stored locally        in the detecting function (such as (R)AN 302 or UPF 304). Stored        QoS violated event reports are sent to a receiving function        (e.g. the SMF or PCF) at predetermined intervals. The        predetermined interval may be included in the QoS monitoring and        QoS violated event reporting policy sent from PCF to the SMF,        and from the SMF to the UPF, and/or (R)AN, and/or UE. In some        embodiments, two or more stored QoS violated event reports may        be encapsulated within a single QNC notification message, so as        to reduce signalling overhead associated with sending multiple        stored QoS violated event reports.    -   Event-based report: QoS violated event reports are stored        locally in the detecting function (such as (R)AN 302 or UPF        304). Stored QoS violated event reports are sent to the        receiving function (e.g. the SMF or PCF) when a predetermined        event occurs. Example events that may trigger transmission of        stored QoS violated event reports include: the UP of the PDU        session is deactivated; the PDU session is released; the UE        associated with the PDU session enters CM-IDLE state; and the UE        transitions from the RRC-CONNECTED state to the RRC-INACTIVE        state.

In the 5G system, each network segment has a delay budget. This meansthat each network segment is designed to meet its own PDB. However, theUP path may consist of multiple UPFs. The current 5G standards do notprovide any means by which a UPF can ensure that the PDB of the CN (as awhole) is satisfied. More particularly, the current 5G standards do notprovide any means by which QoS violated events can be detected, wherethe particular event is that the total transmission delay experienced bya packet exceeds the PDB of the CN.

In some embodiments of the present invention, this problem is addressedby adding a timestamp field in the N3/N9 encapsulation header as shownin FIGS. 4 and 5 ,

FIG. 5 is a block diagram illustrating a method 500 used to transportUser-Plane traffic through a tunnel in the core network. In someembodiments, the tunnel may be a GTP-U tunnel such as tunnel 328 ortunnel 330 described above with reference to FIG. 3 . In general terms,the Protocol Data Unit (PDU) 512 may include a Payload header 508 and aPDU Payload 510. Transport network layers add other header information,for example an L1/L2 header 502, an outer IP header 504, an N3/N9Encapsulation Header (also referred to as an L4 tunnel encapsulationheader) 506.

The L1/L2 header 502 is used to route traffic on specific media, such asoptical cable or wireless link. Those skilled in the art will appreciatethat from the perspective of an L1/L2 entity, the Outer IP header 504,N3, N9 encapsulation header 506 and the payload 512 may all appear to bea payload.

The Outer IP header 504 typically contains IP addresses and UDP portnumbers of the packet source and destination, which will normally be theUPF 304 and the (R)AN node 302. From the perspective of an L3 entity,the N3/N9 encapsulation header 506 and the payload 512 may all appear tobe a part of payload.

The N3/N9 encapsulation header 506 will typically include tunnelspecific information such as a Tunnel Endpoint identifier (TEM)identifying the tunnel 328A, 328B . . . 328N (or tunnel 330), as well asQuality of Service (QoS) Flow Identifier (QFI) and RQI information ofpacket flows within the tunnel 328 (or tunnel 330). Where a non-GTP-Utunnel is employed, other tunnel identifying information may be employedin place of the GTP-U TEID.

The Payload header 508 and Payload 510 comprise the application-layerProtocol Data Unit (PDU) 512 that is sent and received by an applicationexecuting on the ED 102. Typically, the QoS requirement of theapplication-layer PDU 512 is determined by the application executed inthe ED 102, and will normally be indicated by one or more QoS parametersinserted in the Payload header 508.

In some embodiments, the timestamp field may be provided as a new fieldadded to the GTP-U protocol (not shown in FIG. 5 ). Alternatively, thetimestamp field may be placed in an Extension Header of the GTP-Uprotocol. FIG. 6 illustrates an example embodiment in which theconventional sub-fields 602 of the N3/N9 encapsulation header 506 aresupplemented by a timestamp field 604 which may contain one or moretimestamps 606. FIG. 7 illustrates an example network User Plane 700comprising a plurality of UPFs implemented in series between the RAN 302and the DN 306.

When a DownLink (DL) packet destined for a particular UE is received ina PDU Session Anchor (PSA) UPF 304A, e.g. in a buffer of an ingressport, the PSA UPF encapsulates the packet for transport through the corenetwork and inserts a first timestamp, namely Timestamp-1, whichindicates the time that the packet was received by the PSA UPF.

When the packet is sent out from the PSA UPF, a specific function (e.g.packet delay monitoring function) of PCEF checks Timestamp-I of the PDUheader, If the duration the packet stayed in the PSA UPF is longer thanthe packet delay budget of the PSA UPF, or if the packet delay betweenthe time the PDU is sent out of the UPF and Timestamp-1 is larger thanthe PDB, the PCEF of the PSA UPF reports the QoS violated event to theSMF.

The PSA UPF may forward the packet to an Intermediate UPF (I-UPF-1) 304Bover a tunnel, such as N9 tunnel. A specific function (e.g. packet delaymonitoring function) of PCEF may add another timestamp, namelyTimestamp-2. The PCEF of I-UPF-1 may then check the duration betweenTimestamp-1 and Timestamp-2. If this duration is larger than the CN PDB,the PCEF of I-UPF-1 reports this QoS violated event to the SMF.

Similarly, when the packet is sent out of I-UPF-1, a specific functionof PCEF of I-UPF-1 checks the duration that the PDU stayed in I-UPF-1.If this duration is larger than the PDB for this UPF, the UPF may reportthis QoS violated event to the S. If the total duration between the timethe PDU is sent out of I-UPF-1 and Timestamp-1 is larger than the PDB ofCN, the I-UPF may report this QoS violated event to the SMF.

The I-UPF-1 may forward the PDU to another Intermediate UPF (I-UPF-2)304C. The I-UT-2 may monitor the packet delay using similar proceduresas in I-UPF-1.

When the last UPF, UPF-N 304N, of the CN sends the PDU to a (R)AN node302 over the N3 interface, the (R)AN node 302 may monitor the packetdelay in a similar way as the UPFs monitor packet delay described above.Specifically, the (R)AN node 302 may check Timestamp-1 when receivingthe N3 PDU. If the total delayed time (between Timestamp-1 and thecurrent time at the (R)AN node 302) is larger than the predefinedend-to-end PDB, the (R)AN node 302 may report this QoS violated event tothe SMF. Similarly, the (R)AN node may check the total duration thepacket stayed in the (R)AN node. If this duration is larger than theAN-PDB, the (R)AN node may report this QoS violated event to the SMF.

The (R)AN may use the measured PDU delay between the Timestamp-1 and thecurrent time at the (R)AN node to calculate the average packet delay inthe CN in the downlink, in which several measured packet delays ofseveral PDUs are used to calculate the average packet delay in the CN.The (R)AN may report the packet delay of each packet or average packetdelay of QoS flows in the DL to the SMF sent in an N2 SM message.

The (R)AN node may also check the end-to-end delay, between the time thepacket is successfully sent out of (R)AN or the time the (R)AN receivedan acknowledgement from the UE for the packet, and the Timestamp-1. Ifthe total end-to-end delay is larger than the (end-to-end) PDB, the(R)AN may report this QoS violated event to the SMF.

The (R)AN may use the measured total end-tip-end packet delay tocalculate average end-to-end packet delay in the downlink, in whichseveral measured end-to-end packet delays of several PDUs are used tocalculate the average packet delay in the CN. The (R)AN may report thetotal end-to-end packet delay of each packet or average end-to-endpacket delay of QoS flows in the to the SMF sent in an N2 SM message.

Since the (R)AN may use the Timestamp-I to calculate the packet delay inthe CN, the (R)AN may calculate the DL (R)AN PDB in the (R)AN, forexample by taking the total minus the measured DL packet delay oraverage packet delay in the CN. The total PDB is an upper bound for thetime that a packet may be delayed between the UE and the PSA UPF thatterminates the N6 interface. The N6 interface is the interface betweenthe mobile network and the data network. For delay critical QoS flow, ifthe measured packet delay in the CN, and/or the total packet delaybetween the PSA UPF and the UE is larger than the total PDB, the (R)ANmay consider this packet is erroneous and this erroneous packet iscounted in the PER calculation. The (R)AN may use the calculated DL(R)AN PDB for DL packet scheduling.

In the above description, each UPF may add a timestamp to the N3/N9encapsulation header when the UPF receives the PDU. The SMF may use theQoS violated event report to track which network segment may causelonger packet delay.

In the above description, the timestamp(s) is/are added to DL PDUs bythe first PSA UPF, and I-UPF(s), and (JOAN. Similarly, in the UL, the(R)AN I-UPF(s) and PSA UPF may add timestamp to the UL PDUs.

In another embodiment, only the PSA UPF adds the timestamp when itreceives the DL PDU, The UPF (either I-UPF or PSA UPF) that is connectedto the (R)AN by N3 tunnel will check the PDU delay in the CN, beforesending the PDU to the (R)AN. If the PDU delay in CN is larger than theCN PDB, this QoS violated event may reported to the SMF. Similarly, inthe UL, the UPF (either I-UPF or PSA UPF) that is connected to the (R)ANadds the timestamp to the UL PDU when it receives the UL PDU. The PSAUPF will check the packet delay before sending the PDU to DN. If thedelay of UL PDU in the CN is larger than the CN PDB, the PSA UPF reportsthis QoS violated event to the SMF.

In another embodiment, only the (R)AN adds timestamp to the UL PDU. ThePSA UPF will check the end-to-end PDU delay, If the PDU delay is largerthan the PDB, the PSA UPF will report this QoS violated event to theSMF.

The (R)AN may add timestamps to the UL PDU that indicate the currenttime in the (R)AN node and/or the timestamp created by the UE. The PSAUPF timestamp(s) provided by the (R)AN node to calculate the UL packetdelay in the CN and/or the end-to-end packet delay between the UE andthe PSA UPF in the UL. The PSA UPF may use the measured packet delay inthe CN or between the UE and the PSA UPF to calculate the average packetdelay in the CN and/or the end-to-end packet delay between the UE andthe PSA UPF. The PSA UPF may report the average packet delay in the CNor the average end-to-end packet delay between the UE and the PSA UPF inthe UL of the QoS flows to the SMF by a message sent over N4 logicalinterface. FIG. 8 illustrates another method to add timestamps to theN3/N9 encapsulation header. In the embodiment of FIG. 6 , each UPF addsa Timestamp-IN when it receives the PDU, and then adds a Timestamp-OUTwhen it sends out the PDU.

Each next UPF or (R)AN node may check the accumulated timestamps todetect QoS violated events, and the SMF can clearly identify whichnetwork function(s) and transportation segment(s) cause longer packetdelay.

The above description is for the DL PDU, in which the PDU is first sentfrom DN to the PSA UPF. In the UpLink (UL), timestamps can be added tothe N3 or N9 encapsulation header and used to detect QoS violated eventsin a similar manner.

The Timestamp can be carried by adding a new field to the current GTP-Uprotocol defined in 3GPP TS 29.281, published in Dec. 21, 2017.Alternatively, the timestamp can be carried by using an Extension Headerfield of GTP-U protocol, where the Next Extension Header Type indicatesa new type to carry timestamp, e.g., timestamp type, the ExtensionHeader field carries the timestamp. In another embodiment, the timestampcan be carried in one of Extension Header fields of other Next ExtensionHeader Types.

The packet delay events to be reported by UP functions (UPF and (R)AN)to SMF may include:

-   -   Event 1: For the event that the duration the PDU stays in a        particular network function is longer than the PDB for that        network function.    -   Event 2: For the event that the duration between the time the UL        PDU arrives in a particular network function, such as a (R)AN        node, and the time the packet arrives at or is sent out from the        PSA UPF is longer than the PDB.

Event 3: For the event that the duration between the time the DL PDUarrives or is sent out of a network function, such as a (R)AN node, andthe time the packet arrives the PSA UPF is longer than the PDB.

The QoS violated event report may include any one or more of thefollowing information items:

-   -   Event ID,    -   Network Function ID (e.g. (R)AN ID, UPF ID or IP address or        FQDN) that reports the QoS violated event,    -   UE ID (e.g. GPSI, SUPI, TMSI),    -   An identifier to identify Application,    -   packet filter if relevant (in PSA UPF),    -   PDU Session ID    -   PDB of PSA UPF and/or (end-to-end) PDB    -   All the Times amps of network functions    -   The packet delay in PSA UPF    -   The size of PDU    -   A copy of PDU

The packet delay event report may be configured in the PCC rule by aseparate PCC rule parameter, e.g. “Packet Delay Report”. This parametercan be further indicated in the PCC rule to be applied to (R)AN node,and/or UPF, and/or UE. The SMF obtains PCC rules from the PCF when thePDU Session is established or modified.

Based on the packet delay event report in the PCC rule, the SMF may sendto the (R)AN node and UPF, and/or UE a request to add a Timestamp to thePDU, when the PDU arrives at the NF and/or UE, the PDU leaves the NFand/or UE, or when PDU arrives and leaves the NF that serves PDUSession.

The UPF may send the Packet Delay Report to the SME according to thereporting rule received from the SMF by using N4 Report procedure. TheUPF may report the measured packet delay of individual PDUs of QoSflows, the average packet delay of QoS flows in the UL and/or DL, forthe CN segment between the PSA and (R)AN or for the end-to-end packetdelay between the UE and the PSA UPF.

The (R)AN may send the Packet Delay Report to the SMF in N2 SM messages,according to the reporting rule received from the SMF. The (R)AN mayreport the measured packet delay of individual PDUs of QoS flows, theaverage packet delay of QoS flows in the UL and/or DL, for the CNsegment, or for the air interface (may be also called Uu interface).

The UE may send the Packet Delay Report to the SMF according to the rulereceived from the SMF by using N1 SM message sent over the N1 logicalinterface. The UE may report the measured packet delay of individualPDUs of QoS flows, the average packet delay of QoS flows in the ULand/or DL for the end-to-end packet delay between the UE and the PSAUPF.

Alternatively, by default, the timestamp may be added to the N3/N9tunnel header when the QoS violated event report is requested in the PCCrule.

Implementation in TS 23.501

The following paragraphs describe an implementation of embodiments ofthe invention in the context of 3GPP Technical Specification TS 23.501.Such an implementation may incorporate some or all of the elementsdescribed above, in any suitable combination.

Clause 5.7.2.4: Notification Control

A GBR QoS Flow may be associated with the parameter: Notificationcontrol,

The Notification control indicates whether notifications are requestedfrom the (R)AN and/or UPF when the QoS targets can no longer (or again)be fulfilled for a QoS Flow during the lifetime of the QoS Flow.

If, for a given GBR or delay critical GBR QoS Flow, notification controlis enabled and the NG-RAN determines that the GFBR. cannot be fulfilled,(R)AN may send a notification towards SMF. The (R)AN may keep the QoSFlow, and should try to fulfil the GFBR. Upon receiving a notificationfrom the (R)AN that the GFBR cannot be fulfilled, the 5GC may initiateN2 signalling to modify or remove the QoS Flow. When applicable, NG-RANsends a new notification, informing SMF that the GFBR can be fulfilledagain, After a configured time, the NG-RAN may send a subsequentnotification that the GFBR cannot be fulfilled.

If for any QoS Flows, including delay critical GBR QoS Flow,notification control is enabled and the (R)AN node, such as a NG-RANnode, determines that the QoS parameters given in the QoS profiles orpre-configured in the (R)AN node are violated,

-   -   the packet delay of a PM is larger than the 5G-AN PDB;    -   the measured data burst volume within a period of 5G-AN PDB is        larger than the Maximum Data Burst Volume;    -   the measured flow bitrate within the Averaging Window is larger        than the MFBR;    -   the measured Session-AMBR is larger than the authorized Session        BR;    -   the measured LE-AMBR is larger than the subscribed UE-AMBR;    -   a PDU is dropped in a (R)AN node;    -   a measured packet error rate (PER) of a QoS flow of PDU session        is higher than the maximum PER given in the corresponding the        QoS profile for this QoS flow at the (R)AN node; and    -   a QoS flow is released due to the lack of network resources.

The (R)AN may send a notification towards the SMF. The notification fordelay critical GBR QoS Flows includes time stamp of the event, PDUSession ID, QFI, the name of violated QoS parameter, and the measuredvalue of violated QoS parameter. If the packet delay is larger than the5G-AN PDB, the notification additionally includes the packet size.

The SMF can be configured by the PCF how often the notification from(R)AN is forwarded to the PCF: immediately, periodically, orevent-based, when the UP of PDU Session is deactivated, when the UEenters CM-IDLE state, or when the PDU Session is released. Theperiodicity of event reporting may be included in the QoS monitoring andQoS violated event reporting policy sent from PCF to the SMF.

QoS Violated Event Report

For any QoS Flows, including GBR and delay critical GBR QoS Flow, theparameter QoS violated event Report is used to indicate whether the UPFmay report QoS violated events,

-   -   the packet delay of the PDU is larger than the UPF PDB;    -   the measured data burst volume within a period of UPF PDB is        larger than the Maximum Data Burst Volume; and    -   the measured flow bitrate within the Averaging Window is larger        than the MFBR,    -   the UPF cannot support the GFBR,    -   the measured Session-AMBR is larger than the authorized        Session-AMBR,    -   the measured UE-AMBR is larger than the subscribed UE-AMBR.    -   a PDU is dropped in a UPF; and    -   a measured packet error rate (PER) of a QoS flow of a PDU        session is higher than the maximum PER given in the        corresponding PCC rule for this QoS flow at the UPF.

The UPF may send QoS violated event reports to the SMF. The SMF can beconfigured by the PCF how often the notification from UPF is forwardedto the PCF: immediately, periodically, or event-based, when the UP ofPDU Session is deactivated, or when the PDU Session is released.

Implementation in TS 23.502

The following paragraphs describe an implementation of embodiments ofthe invention in the context of 3GPP Technical Specification TS 23.502.Such an implementation may incorporate some or all of the elementsdescribed above, in any suitable combination.

Clause 4.3.2.1: Non-Roaming and Roaming with Local Breakout

Clause 4.3.2.2.1 specifies PDU session establishment in the non-roamingand roaming with local breakout cases. The procedure is used to:

-   -   Establish a new PDU Session;    -   Handover a PDN Connection in EPS to PDU Session in 5GS without        N26 interface;    -   Switching an existing PDU Session between non-3GPP access and        3GPP access. The specific system behaviour in this case is        further defined in clause 4.9.2 of TS 23 502; or    -   request a PDU Session for Emergency services.

In case of roaming, the AMF determines if a PDU Session is to beestablished in LBO or Home Routing. In the case of LBO, the procedure isas in the case of non-roaming with the difference that the AMF, the SMF,the UPF and the PCF are located in the visited network. PDU Sessions forEmergency services are never established in Home Routed mode.

UE-Requested PDU Session Establishment for Non-Roaming and Roaming withLocal Breakout

FIGS. 9A-9B illustrate a representative process for UE-requested. PDUSession Establishment for non-roaming and roaming with local breakout.This procedure assumes that the UE has already registered on the AMFthus unless the UE is Emergency registered the AMF has already retrievedthe user subscription data from the UDM.

Step 1: From UE to AMF: NAS Message (S-NSSAI(s), DNN, PDU Session ID,Request type, Old PDU Session ID, N1 SM container (PDU SessionEstablishment Request)).

-   -   In order to establish a new PDU Session, the UE generates a new        PDU Session ID.    -   The UE initiates the UE Requested PDU Session Establishment        procedure by the transmission of a NAS message containing a PDU        Session Establishment Request within the N1 SM container. The        PDU Session Establishment Request may include a Requested PDU        Type, a Requested SSC mode, Protocol Configuration Options, SM        PDU DN Request Container.    -   The Request Type indicates “Initial request” if the PDU Session        Establishment is a request to establish a new PDU Session and        indicates “Existing PDU Session” if the request refers to an        existing PDU Session switching between 3GPP access and non-3GPP        access or to a PDU Session handover from an existing PDN        connection in EPC, If the request refers to an existing PDN        connection in EPC, the S-NSSAI is set based on the S-NSSAI        received from PCO which is sent by PGW-C+SMF during PDN        Connection Establishment procedure. When Emergency service is        required and an Emergency PDU Session is not already        established, a UE may initiate the UE Requested PDU Session        Establishment procedure with a Request Type indicating        “Emergency Request”.    -   The Request Type indicates “Emergency Request” if the PDU        Session Establishment is a request to establish a PDU Session        for Emergency services. The Request Type indicates “Existing        Emergency PDU Session” if the request refers to an existing PDU        Session for Emergency services switching between 3GPP access and        non-3GPP access.    -   The NAS message sent by the UE is encapsulated by the AN in a N2        message towards the AMF that should include User location        information and Access Technology Type Information.    -   The PDU Session Establishment Request message may contain SM PDU        DN Request Container containing information for the PDU Session        authorization by the external DN.    -   The UE includes the S-NSSAI from the Allowed NSSAI. If the        Mapping of Allowed NSSAI was provided to the UE, the UE may        provide both the S-NSSAI from the Allowed NSSAI and the        corresponding S-NSSAI from the Configured NSSAI for the HPLMN.    -   If the procedure is triggered for SSC mode 3 operation, the UE        may also include: the Old PM Session ID which indicates the PDU        Session ID of the on-going PDU Session to be released, in NAS        message. The Old PDU Session ID is an optional parameter which        is included only in this case.    -   The AMF receives from the AN the NAS SM message (built in step        1) together with User Location Information e.g. Cell Id in case        of the (R)AN).    -   The UE may not trigger a PDU Session establishment for a PDU        Session corresponding to a LADN when the UE is outside the area        of availability of the LADN.

Step 2: The AMF determines that the message corresponds to a request fora new PDU Session based on that Request Type indicates “initial request”and that the PDU Session ID is not used for any existing PDU Session(s)of the UE. If the NAS message does not contain an S-NSSAI, the AMF maydetermine a default S-NSSAI for the requested PDU Session eitheraccording to the UE subscription, if it contains only one defaultS-NSSAI, or based on operator policy.

-   -   The AMF selects an SMF as described in clause 4.3.12.3 of TS        23.502. If the Request Type indicates “Initial request” or the        request is due to handover from EPS, the AMF stores an        association of the S-NSSAI(s), the DNN, the PDU Session ID and        the SMF ID.    -   if the Request Type is “initial request” and if the Old PDU        Session ID indicating the existing PDU Session is also contained        in the message, the AMF selects an SMF as described in clause        4.3.5.2. of TS 23.502 and stores an association of the new PDU        Session ID, the S-NSSAI and the selected SMF ID.    -   If the Request Type indicates “Existing PDU Session”, the AMF        selects the SMF based on SMF-ID received from UDM. The case        where the Request Type indicates “Existing PDU Session”, and        either the AMF does not recognize the PDU Session ID or the        subscription context that the AMF received from UDM during the        Registration or Subscription Profile Update Notification        procedure does not contain an SMF ID corresponding to the PDU        Session ID constitutes an error case.    -   if the Request Type indicates “Existing PDU Session” referring        to an existing PDU Session moved between 3GPP access and        non-3GPP access, then if the SMF ID (H-SMF in home-routed case)        corresponding to the PDU Session ID and the AMF belong to the        same PLMN, the PDU Session Establishment procedure can be        performed, otherwise the AMF may reject the PDU Session        Establishment Request with an appropriate reject cause.    -   NOTE 1: The SMF ID includes the PLMN ID that the SMF belongs to.    -   The AMF may reject a request coming from an UE when the UE is        registered for Emergency services and the Request Type indicates        neither “Emergency Request” nor “Existing Emergency PDU        Session”. When the Request Type indicates “Emergency Request”,        the AMF is not expecting any S-NSSAI and DNN value provided by        the UE and uses locally configured values instead.    -   If the Request Type indicates “Emergency Request” or “Existing        Emergency PDU Session”, the AMF selects the SMF as described in        TS 23.501 [2], clause 5.16.4.

Step 3: From AMF to SMF: Either Nsmf_PDUSession_CreateSMContext Request(SUN, DNN, S-NSSAI, PDU Session ID, AMF ID, Request Type, N1 SMcontainer (PDU Session Establishment Request), User locationinformation, Access Type, PEI, GPSI, Subscription For PDU Session StatusNotification) or Nsmf_PDUSession_UpdateSMContext Request (SUPI, DNN,S-NSSAI, PDU Session ID, AMF ID, Request Type, N1 SM container (PDUSession Establishment Request), User location information, Access Type,RAT type, PEI),

-   -   if the AMF does not have an association with an SMF for the PDU        Session ID provided by the UE (e.g. when Request Type indicates        “initial request”), the AMF invokes the Nsmf PDUSession        CreateSMContext Request, but if the AMF already has an        association with an SMF for the PDU Session ID provided by the        UE (e.g. when Request Type indicates “existing PDU Session”),        the AME invokes the Nsmf_PDUSession_UpdateSMContext Request.    -   The AMF ID is the UE's GUAMI which uniquely identifies the AMF        serving the UE. The AMF forwards the PDU Session ID together        with the N1 SM container containing the PDU Session        Establishment Request received from the UE. The GPSI may be        included if available at AMF.    -   The AMF provides the PEI instead of the SUN when the UE has        registered for Emergency services without providing a SURF. The        P.E.I. is defined in TS 23.501 [2] clause 5.9.3. In case the UE        has registered for Emergency services with a SUPI but has not        been authenticated the AMF indicates that the SUPI has not been        authenticated. The SMF determines that the UE has not been        authenticated when it does not receive a SUN for the UE or when        the AMF indicates that the SUN has not been authenticated.    -   if the Old PDU Session ID is included in step 1, and if the SMF        is not to be reallocated, the AMF also includes Old PDU Session        ID in the Nsmf PDUSession CreateSMContext Request.    -   In the local breakout case, if the V-SMF is not able to process        some part of the N1 SM information then Home Routed Roaming is        required, and the V-SMF responds to the AMF that it is not the        right SMF to handle the N1 SM message by invoking        Nsmf_PDUSession_CreateSM Response service operation. The V-SMF        includes a proper N11 cause code triggering the AMF to proceed        with home routed case. The procedure starts again at step 2 of        clause 4.3.2.2.2 of TS 23.502.

Step 4: If Request Type in step 3 indicates neither “Emergency Request”nor “Existing Emergency PDU Session” and, if the SMF has not yetregistered for this PDU Session ID, then the SMF registers with the UDMusing Nudm_UECM_Registration (SUPI, DNN, PDU Session ID) for a given PDUSession. As a result, the UDM stores following information: SUN, SMFidentity, SMF address and the associated DNN and PDU Session ID. IfSession Management Subscription data for corresponding SUPI, DNN andS-NSSAI is not available, then SMF retrieves the Session ManagementSubscription data using Nudm_SDM_Get (SUPI, DNN, S-NSSAI) and subscribesto be notified when this subscription data is modified usingNudm_SDM_Subsctibe (SUPI, DNN, S-NSSAI).

-   -   If the Request Type received in step 3 indicates “Emergency        Request”        -   For an authenticated non-roaming UE, based on operator            configuration (e.g. related with whether the operator uses a            fixed SMF for Emergency calls, etc.), the SMF may register            in the UDM using Nudrn:UECM_Registration (SUPI, PDU Session            ID, Indication of Emergency Services) for a given PDU            Session that is applicable for emergency services. As a            result, the UDM may store the SMF address and the applicable            PDU Session for Emergency services.        -   For an unauthenticated UE or a roaming UE, the SMF may not            register in the UDM for a given PDU Session.    -   If the Request Type in step 3 indicates “Existing PDU Session”        or “Existing Emergency PDU Session” the SMF determines that the        request is due to switching between 3GPP access and non-3GPP        access or due to handover from EPS. The SMF identifies the        existing PDU Session based on the PDU Session ID. In such a        case, the SMF does not create a new SM context but instead        updates the existing SM context and provides the representation        of the updated. SM context to the AMF in the response.    -   If the Request Type is “Initial request” and if the Old PDU        Session ID is included in Nsmf_PDUSession_CreateSMContext        Request, the SMF identifies the existing PDU Session to be        released based on the Old PDU Session ID.    -   Subscription data includes the authorized PDU type(s) authorized        SSC mode(s), default 5QI and ARP, subscribed Session-AMBR.    -   Static IP address/prefix may be included in the subscription        data if the UE has subscribed to it.    -   The SMF checks the validity of the UE request: it checks        -   whether the LTE request is compliant with the user            subscription and with local policies;        -   (If the DNN corresponds to an LADN), whether the UE is            located within the LADN service area based on the UE            location reporting from the AMF.    -   If the UE request is considered as not valid, the SMF decides to        not accept to establish the PDU Session.

Step 5: From SMF to AMF: Either Nsmf_PDUSession_CreateSMContextResponse(Cause, SM Context II) or N1 SM container (PDU SessionReject(Cause))) or an Nsmf_PDUSession_UpdateSMContext Response dependingon the request received in step 3.

-   -   If the SMF received Nsmf_PDUSession_CreateSMContext Request in        step 3 and the SMF is able to process the PDU Session        establishment request, the SMF creates an SM context and        responds to the AMF by providing an SM Context Identifier.    -   When the SMF decides to not accept to establish a PDU Session,        the SMF rejects the UE request via NAS SM signalling including a        relevant SM rejection cause by responding to the AMF with        Nsmf_PDUSession_CreateSMContext Response. The SMF also indicates        to the AMF that the PDU Session ID is to be considered as        released, deregisters from UDM for this PDU Session and the rest        of the procedure is skipped.

Step 6: Optional Secondary authorization/authentication.

-   -   If the Request Type in step 3 indicates “Existing PDU Session”,        the SMF does not perform secondary authorization/authentication.    -   If the Request Type received in step 3 indicates “Emergency        Request” or “Existing Emergency PDU Session”, the SMF may not        perform secondary authorization/authentication.    -   If the SMF needs to perform secondary        authorization/authentication during the establishment of the PDU        Session by a DN-AAA server as described in TS 23.501 [2] clause        5.6.6, the SMF triggers the PDU Session establishment        authentication/authorization as described in clause 4.3.2.3 of        TS 23.502.    -   If the PDU Session establishment authentication/authorization        fails, the SMF proceeds to step 19 and the PDU Session        Establishment procedure is stopped.

Step 7 a: If dynamic PCC is deployed, the SMF performs PCF selection. Ifthe Request Type indicates “Existing PDU Session” or “Existing EmergencyPDU Session”, the SMF may use the PCF already selected for the PDUSession.

-   -   If dynamic PCC is not deployed, the SMF may apply local policy.

Step 7 b: The SMF may perform a Session Management Policy Establishmentprocedure as defined in clause 4.16.4 to establish a PDU Session withthe PCF and get the default PCC Rules for the PDU Session. The GPSI maybe included if available at SW. If the Request Type in step 3 indicates“Existing PDU Session”, the SMF may notify an event previouslysubscribed by the PCF by a Session Management Policy Modificationprocedure as defined in clause 4.16.5 and the PCF may update policyinformation in the SMF. The PCF may provide authorized Session-AMBR andthe authorized 5QI and ARP to SMF. The PCF subscribes to the IPallocation/release event in the SMF (and may subscribe other events).

-   -   The PCF, based on the Emergency DNN, sets the ARP of the PCC        rules to a value that is reserved for Emergency services as        described in TS 23.503 [20].

NOTE 2: The purpose of step 7 is to receive PCC rules before selectingUPF. If PCC rules are not needed as input for UPF selection, step 7 canbe performed after step 8.

As explained earlier and later in the present document, the PCC Rulesinclude the QoS Violated Event Reporting Rule.

Step 8: If the Request Type in step 3 indicates “Initial request”, theSMF selects an SSC mode for the PDU Session as described in TS 23.501[2] clause 5.6.9.3. The SMF also selects one or more UPFs as needed asdescribed in TS 23.501 [2] clause 6.3.3. In case of PDU Type IPv4 orIPv6, the SMF allocates an IP address/prefix for the PDU Session asdescribed in TS 23.501 [2] clause 5.8.1. In case of PDU Type IPv6, theSMF also allocates an interface identifier to the UE for the UE to buildits link-local address. For Unstructured PDU Type the SMF may allocatean IPv6 prefix for the PDU Session and N6 point-tip-point tunnelling(based on UDP/IPv6) as described in TS 23.501 [2] clause 5,6.10.3. ForEthernet PDU type PDU Session, neither a MAC nor an IF address isallocated by the SMF to the UE for this PDU Session.

-   -   If the Request Type in Step 3 is “Existing PDU Session”, the SMF        maintains the same IP address/prefix that has already been        allocated to the UE in the source network.    -   If the Request Type in step 3 indicates “Existing PDU Session”        referring to an existing PDU Session moved between 3GPP access        and non-3GPP access the SMF maintains the SSC mode of the PDU        Session, the current PDU Session Anchor and IP address.

NOTE 3 The SMF may decide to trigger e.g. new intermediate UPF insertionor allocation of a new UPF as described in step 5 in clause 4.2.3.2 ofTS 23.502.

-   -   If the Request Type indicates “Emergency Request”, the SMF        selects the UPF as described in TS 23.501 [2], clause 5.16.4 and        selects SSC mode 1.

Step 9: SMF may perform a Session Management Policy Modificationprocedure as defined in clause 4.16.5 to report some event to the PCFthat has previously subscribed. If Request Type is “initial request” anddynamic PCC is deployed and PDU Type is IPv4 or IPv6, SMF notifies thePCF (that has previously subscribed) with the allocated UE IPaddress/prefix.

NOTE 4: If an FP address/prefix has been allocated before step 7 (e.g.subscribed static IP address/prefix in UDM) or the step 7 is performafter step 8, the IP address/prefix can be provided to PCF in step 7,and the IP address/prefix notification in this step can be skipped.

Step 9: PCF may provide updated policies to the SMF. The PCF may provideauthorized Session-AMBR and the authorized 5Q1 and ARP to SMF.

As explained earlier and later in the present document, the PCC Rulessent from the PCF to the SMF may include the QVER Rule. Step 10: IfRequest Type indicates “initial request”, the SMF initiates an N4Session Establishment procedure with the selected UPF, otherwise itinitiates an N4 Session Modification procedure with the selected UPF:

-   -   10 a: The SMF sends an N4 Session Establishment/Modification        Request to the UPF and provides Packet detection, enforcement        and reporting rules to be installed on the UPF for this PDU        Session. If CN Tunnel info is allocated by the SMF, the CN        Tunnel Info is provided to UPF in this step. If the selective        User Plane deactivation is required for this PDU Session, the        SMF determine the Inactivity Timer and it provides to the UPF.        If the timestamp is required for ingress (incoming) and/or        egress (outgoing) PDU, the SMF provides the indication to add        Timestamp to Ingress PDU and/or Timestamp to Egress PDU as one        of parameters to the UPF.    -   As explained earlier and later in the present document, the N4        Session Establishment/Modification Request sent from the SMF to        the UPF may include the QVER Rule. If the QVER Rule includes        packet delay reporting and/or packet delay violation event,        and/or PER violation event, and/or MDBV violation event, the UPF        may add timestamp to the PDUs indicating the time the PDUs        arrive and/or leave the UPF, The UPF sends the PDUs with        timestamp(s) toward the (R)AN node over the N3 or N9        interface.10 b: The UPF acknowledges by sending an N4 Session        Establishment/Modification Response. If CN Tunnel Info is        allocated by the UPF, the CN Tunnel Info is provided to SMF in        this step.    -   if multiple UPFs are selected for the PDU Session, the SMF        initiate N4 Session Establishment/Modification procedure with        each UPF of the PDU Session in this step.

If the Request Type indicates “Existing PDU Session”, and the SMFcreates CN Tunnel Info, then this step is skipped. Otherwise, this stepis performed to obtain the CN Tunnel Info from the UPF using the N4Session Modification Procedure. Step 11: SMF to AMF:Namf_Communication_N1N2MessageTransfer (PDU Session ID, Access Type, N2SM information (PDU Session ID, QFI(s), QoS Profile(s), CN Tunnel Info,S-NSSAI, Session-AMBR, PDU Session Type), N1 SM container (PDU SessionEstablishment Accept (QoS Rule(s), selected SSC mode, S-NSSAI, allocatedIPv4 address, interface identifier, Session-AMBR, selected PDU SessionType))). In case of multiple UPFs are used for the PDU Session, the CNtunnel Info contain tunnel information related with the UPF thatterminates N3.

-   -   The N2 SM information carries information that the AMF may        forward to the (R)AN which includes:        -   The CN Tunnel info corresponds to the Core Network address            of the N3 tunnel corresponding to the PDU Session.        -   One or multiple QoS profiles and the corresponding QFIs can            be provided to the (R)AN. This is further described in TS            23.501 [2] clause 5.7.        -   The PDU Session ID may be used by AN signalling with the UE            to indicate to the UE the association between AN resources            and a PDU Session for the UE.    -   A PDU Session is associated to an S-NSSAI and a DNN.    -   The N1 SM container contains the PDU Session Establishment        Accept that the AMF may provide to the UE.    -   Multiple QoS Rules and QoS Profiles may be included in the PDU        Session Establishment Accept within the N1 SM and in the N2 SM        information.    -   The Namf_Communication_N1N2MessageTransfer further contains the        PDU Session ID and information allowing the AMF to know which        access towards the UE to use,

NOTE 5: The access information is to deal with the case where a UE issimultaneously connected over 3GPP and Non 3GPP access.

As introduced earlier and later in the present document, the N2 SMmessage sent from the SMF to the (R)AN may include the QVER Rule. The N1SM message sent from the SMF to the UE may including QVER Rule.

Step 12: AMF to (R)AN: N2 PDU Session Request (N2 SM information, NASmessage (PDU Session ID, N1 SM container (PDU Session EstablishmentAccept))).

-   -   The AMF sends the NAS message containing PDU Session ID and PDU        Session Establishment Accept targeted to the UE and the N2 SM        information received from the SMF within the N2 PDU Session        Request to the (R)AN.

As introduced earlier and later in the present document, the messagesent from the SMF to the (R)AN may include the QVER. Rule. if the QVERRule includes packet delay reporting, and/or packet delay violationevent, and/or PER violation event, and/or MDBV violation event, the(R)AN may add timestamp to the DL and/or UL PDUs indicating the time(s)the PDUs arrives and/or leaves the (R)AN. The (R)AN sends the PDUs withtimestamp(s) toward the PSA UPF node over the N3 or N9 interface.

Step 13: (R)AN to UE: The (R)AN may issue AN specific signallingexchange with the UE that is related with the information received fromSMF. For example, in case of a 3GPP (R)AN, an RRC ConnectionReconfiguration may take place with the UE establishing the necessary(R)AN resources related to the QoS Rules for the PDU Session requestreceived in step 12

-   -   (R)AN also allocates (R)AN N3 tunnel information for the PDU        Session. In case of Dual Connectivity, the Master (R)AN node may        assign some (zero or more) QFIs to be setup to a Master (R)AN        node and others to the Secondary (R)AN node. The AN Tunnel Info        includes a tunnel endpoint for each involved (R)AN node, and the        QFIs assigned to each tunnel endpoint. A QFI can be assigned to        either the Master (R)AN node or the Secondary (R)AN node and not        to both.    -   (R)AN forwards the NAS message (PDU Session ID, N1 SM container        (PDU Session Establishment Accept)) provided in step 12 to the        UE. (R)AN may only provide the NAS message to the UE if the        necessary (R)AN resources are established and the allocation of        (R)AN tunnel information are successful.

As introduced earlier and later in the present document, the messagesent from the SMF to the UE may include the QVER Rule. If the QVER Ruleincludes packet delay reporting, and/or packet delay violation event,and/or PER violation event, and/or MDBV violation event, the UE may addtimestamp to the PDUs indicating the time the PDUs arrives and/or leavesthe UE. The UE sends the PDU with timestamp(s) toward the (R)AN nodeover the air interface Uta. The UE may read the timestamp(s) of the DLPDU(s) to calculate the end-to-end packet delay between the PSA tiffand/or the delay of RAN between the (R)AN node and the UE.

Step 14: (R)AN to AMP: N2 PDU Session Response (PDU Session ID, Cause,N2 SM information (PDU Session ID, AN Tunnel Info, List ofaccepted/rejected QFI(s))).

-   -   The AN Tunnel Info corresponds to the Access Network address of        the N3 tunnel corresponding to the PDU Session.

Step 15: AMF to SMF: Nsmf_PDUSession_UpdateSMContext Request (N2 SMinformation, Request Type).

-   -   The AMF forwards the N2 SM information received from (R)AN to        the SMF.    -   If the list of rejected QFI(s) is included in N2 SM information,        the SMF may release the rejected QFI(s) associated QoS profiles.

Step 16 a: The SMF initiates an N4 Session Modification procedure withthe UPF. The SMF provides AN Tunnel Info to the UPF as well as thecorresponding forwarding rules.

As introduced earlier and later in the present document, the messagesent from the SMF to the UPF may include the QVER Rule. If the QVER Ruleincludes packet delay reporting, and/or packet delay violation event,and/or PER violation event, and/or MDBV violation event, the UPF may addtimestamp to the PDUs indicating the time the PDUs arrives and/or leavesthe UPF. The UPF sends the PDU with timestamp(s) toward the (R)AN nodeover the N3 or N9 interface. NOTE 6: If the PDU Session EstablishmentRequest was due to mobility between 3GPP and non-3GPP access or mobilityfrom EPC, the downlink data path is switched towards the target accessin this step.

Step 16 b: The UPF provides an N4 Session Modification Response to theSMF.

-   -   If multiple UPFs are used in the PDU Session, the UPF in step 16        refers to the UPF terminating N3.

Step 17: SMF to AMF: Nsmf_PDUSession_UpdateSMContext Response (Cause).

-   -   The SMF may subscribe to the UE mobility event notification from        the AMF (e.g. location reporting, UE moving into or out of area        of interest), after this step by invoking        Namf_EventExposure_Subscribe service operation as specified in        clause 5.2.2.3.2 of TS 23.502. For LADN, the SMF subscribes to        the UE moving into or out of LADN service area event        notification by providing the LADN DNN as an indicator for the        area of interest (see clause 5.6.5 and 5.6.11 of TS 23.501 [2]).    -   After this step, the AMF forwards relevant events subscribed by        the SMF.

Step 18: [Conditional] SMF to AMF: Nsmf_PDUSession_SMContextStatusNotify(Release)

-   -   If during the procedure, any time after step 5, the PDU Session        establishment is not successful, the SMF informs the AMF by        invoking Nsmf_PDUSession_SMContextStatusNotify(Release). The SMF        also releases any N4 session(s) created, any PDU Session address        if allocated (e.g IP address) and releases the association with        PCF, if any.

Step 19: SMF to LT, via UPF: In case of PDU Type IPv6, the SMF generatesan IPv6 Router Advertisement and sends it to the UE via N4 and the UPF.

Step 20: If the PDU Session cannot be established, then the SMF mayperform the following:

-   -   a) The SMF unsubscribes to the modifications of Session        Management Subscription data for the corresponding (SUPI, DNN,        S-NSSAI), using Nudm SDM Unsubscribe (SUPI, DNN, S-NSSAI), if        the SMF is no more handling a PDU Session of the UE for this        (DNN, S-NSSAI).    -   b) The SMF deregisters for the given PDU Session using        Nudm_UECM_Deregistration (SUPI, DNN, PDU Session ID).        UE-Requested NW Session Establishment for Home-Routed Roaming        Scenarios

FIGS. 10A-10C: illustrate a representative process for UE-requested PDUSession Establishment for home-routed roaming scenarios.

Step 1: This step is the same as step 1 of FIGS. 9A-9B.

Step 2: As in step 2 of FIGS. 9A-9B with the addition that the AMF alsoselects a SMF in HPLMN using the S-NSSAI with the value defined by theHPLMN, as described in clause 4.3.2.2.3. The AMF stores the associationof the S-NSSAI, the DNN, the PDU Session ID and the SMF ID in VPLMN.

In step 3 of FIGS. 9A-9B, in local breakout roaming case, if V-SMFresponds to AMF indicating that V-SMF is not able to process some partof the N1 SM information, the AMF proceeds with home routed case fromthis step and may select an SMF in the VPLMN different from the V-SMFselected earlier.

Step 3 a: As in step 3 of FIGS. 9A-9B with the addition that the AMFalso provides the identity of the SMF in HPLMN it has selected in step 2and the S-NSSAI with the value defined by the HPLMN. The H-SMF isprovided when the PDU Session is home-routed. The N1 SM containercontains the PDU Session Establishment Request received from the UE.GPSI may be provided to the V-SMF by the AMF if available at AMF.

3 b: This step is the same as step 5 of FIGS. 9A-9B.

Step 4: The V-SMF selects a UPF in VPLMN as described in TS 23.501 [2],clause 6.3.3.

In Step 5 The V-SMF initiates an N4 Session Establishment procedure withthe selected V-UPF:

-   -   5 a: The V-SMF sends an N4 Session Establishment Request to the        V-UPF. If CN Tunnel Info is allocated by the SMF, the CN Tunnel        Info is provided to V-UPF in this step. If the timestamp is        required for ingress (incoming) and/or egress (outgoing) PDU,        the V-SMF provides an indication to add the Timestamp to Ingress        PDU and/or Timestamp to Egress PDU as one of parameters to the        V-UPF.    -   5 b: The V-UPF acknowledges by sending an N4 Session        Establishment Response. If CN Tunnel Info is allocated by the        V-UPF, the CN Tunnel Info is provided to V-SMF in this step.

As introduced earlier and later in the present document, the messagesent from the V-SMF to the V-UPF may include the QVER Rule. If the QVERRule includes packet delay reporting, and/or packet delay violationevent, and/or PER violation event, and/or MDBV violation event, theV-UPF may add timestamp to the PDUs indicating the time the PDUs arrivesand/or leaves the V-UPF. The V-UPF may send the PDUs with timestamp(s)toward the (R)AN node over the N3 or N9 interface. The V-UPF may sendthe PDUs with timestamp(s) toward the

Step 6: V-SMF to H-SMF: Nsmf_PDUSession_Create Request (SUPI, GPSI (ifavailable), DNN, S-NSSAI with the value defined by the HPLMN, PDUSession ID, V-SMF ID, V-CN-Tunnel-Info, PDU type, Protocol ConfigurationOptions, User location information, SM PDU DN Request Container).Protocol Configuration Options may contain information that H-SMF mayneeds to properly establish the PDU Session (e.g. SSC mode or SM PDU DNRequest Container to be used to authenticate the UE by the DN-AAA asdefined in clause 4.3.2.3).

Steps 7-12 a, 12 b: These steps are the same as steps 4-10 in FIGS.9A-9B with the following differences:

-   -   These steps are executed in Home PLMN;    -   The H-SMF stores an association of the VDU Session and V-SMF ID        for this PDU Session for this UE.    -   The H-SMF does not provides the Inactivity Timer to the H-UPF as        described in step 9 a in clause 4.3.2,2.1.    -   Step 5 of FIGS. 9A-9B is not executed.

As introduced earlier and later in the present document, the messagesent from the H-SMF to the H-UPF may include the QVER Rule. If the QVERRule includes packet delay reporting, and/or packet delay violationevent, and/or PER violation event, and/or MDBV violation event, theH-UPF may add timestamp to the PDUs indicating the time the PDUs arrivesand/or leaves the H-UPF. The H-UPF may sends the PDUs with timestamp(s)toward the V-UPF.

Step 13: H-SMF to V-SMF: Nsmf_PDUSession_Create Response (QoS Rule(s),Protocol Configuration Options including session level information thatthe V-SMF is not expected to understand, selected PDU Session Type andSSC mode, H-CN Tunnel Info, QFI(s), QoS profile(s), Session-AMBR,information needed by V-SMF in case of EPS interworking such as the PDNConnection Type)

-   -   The information that the H-SMF may provide is the same as that        defined for step 11 of FIGS. 9A-9B.    -   The H-CN Tunnel Info contains the tunnel information for uplink        traffic towards H-UPF.    -   Multiple QoS Rules may be included in the Nsmf_PDUSession_Create        Response.

Steps 14-18: These steps are the same as steps 11-15 FIGS. 9A-9B withthe following differences:

-   -   These steps are executed in Visited PLMN;    -   The V-SMF stores an association of the PDU Session and H-SMF ID        for this PDU Session for this UE.

19 a: The V-SW initiates an N4 Session Modification procedure with theV-UPF. The V-SMF provides Packet detection, enforcement and reportingrules to be installed on the V-UPF for this PDU Session, including ANTunnel Info, I-i-CN Tunnel Info and V-CN Tunnel Info. If the timestampis required for measuring packet delay for ingress (incoming) and/oregress (outgoing) PDU, the V-SMF provides the PCC rule that includes anindication that the Timestamp to be added to the Ingress PDU andTimestamp to be added to the Egress PDU as one of parameters to theV-UPF.

Step 19 b: The V-UPF provides a N4 Session Modification Response to theV-SMF.

-   -   After this step, the V-UPF delivers any down-link packets to the        UE that may have been buffered for this PDU Session.

The message sent from the V-SMF to the V-UPF may include the QVER Rule.If the QVER Rule includes packet delay reporting, and/or packet delayviolation event, and/or PER violation event, and/or MDBV violationevent, the V-UPF may add timestamp to the PDUs indicating the time thePDUs arrives and/or leaves the V-UPF. The V-LPF may send the PDUs withtimestamp(s) toward the (R)AN node over the N3 or N9 interface. TheV-UPF may send the PDUs with timestamp(s) toward the H-UPF.

Step 20: This step is the same as step 17 in FIGS. 9A-9B. with thefollowing differences:

-   -   The SMF is a V-SMF

Step 21: This step is same as step 18 in FIGS. 9A-9B.

Step 22: H-SMF to UE, via H-UPF and V-UPF in VPLMN: In case of PDU TypeIPv6, the H-SMF generates an IPv6 Router Advertisement and sends it tothe UE via N4 and the H-UPF and V-UPF.

Step 23: This step is the same as step 20 in FIGS. 9A-9B with thedifference that this step is executed in the Home PLMN.

NOTE: The SMF in HPLMN can initiate step 21 already after step 13.

UE or Network Requested MU Session Modification (Non-Roaming and Roamingwith Local Breakout)

FIGS. 11A and 11B illustrate UE or network requested PDU SessionModification procedure (non-roaming and roaming with local breakout).

Step 1: The procedure may be triggered by following events:

-   -   1 a: (UE initiated modification) The UE initiates the PDU        Session Modification procedure by the transmission of an NAS        message (N1 SM container (PDU Session Modification        Request(Packet Filters, Operation, Requested QoS, Segregation)),        PDU Session ID) message. Depending on the Access Type, if the UE        was in CM-IDLE state, this SM-NAS message is preceded by the        Service Request procedure. The NAS message is forwarded by the        (R)AN to the AMF with an indication of User location        Information. The AMF invokes Nsmf_PDUSession_UpdateSMContex (PDU        Session ID, N1 SM container (PDU Session Modification Request)).    -   When the UE requests specific QoS handling for selected SDF(s),        the PDU Session Modification Request includes Packet Filters        describing the SDF(s), the requested Operation (add, modify,        delete), the Requested QoS and optionally a Segregation        indication. The Segregation indication is included when the UE        recommends to the network to bind the applicable SDF(s) on a        distinct and dedicated QoS Flow e.g. even if an existing QoS        Flow can support the requested QoS. The network should abide by        the UE request, but is allowed to proceed instead with binding        the selected SDF(s) on an existing QoS Flow.    -   NOTE I: Only one QoS Flow is used for traffic segregation. If UE        makes subsequent requests for segregation of additional SDF(s),        the additional SDF(s) are multiplexed on the existing QoS Flow        that is used for segregation.    -   The UE may not trigger a PDU Session Modification procedure for        a PDU Session corresponding to a LADN when the UE is outside the        area of availability of the LADN.    -   1 b: (SMF requested modification) The PCF performs a Session        Management Policy Modification procedure as defined in clause        4.16.5 of 3GPP TS 23.502 to notify SMF about the modification of        policies. This may e.g.; have been triggered by a policy        decision or upon AF requests.

The AF may request the PCF to the report the QoS violated events. ThePCF may send QVER Rule to the SMF.

-   -   1 c: (SMF requested modification) The UDM updates the        subscription data of SMF by        Nudm_SubscriberData_UpdateNotification (SUPI, Subscription        Data). The SMF updates the Subscription Data and acknowledges        the UDM by returning an Ack with (SUPI).    -   1 d: (SMF requested modification) The SMF may decide to modify        PDU Session. This procedure also may be triggered based on        locally configured policy or triggered from the (R)AN (see        clause 4.2.6).    -   If the SMF receives one of the triggers in step 1 b˜1 d, starts        SMF requested PDU Session Modification procedure.    -   1 e: (AN initiated modification) (R)AN may indicate to the SMF        when the AN resources onto which a QoS flow is mapped are        released. (R)AN sends the N2 message (PDU Session ID, N2 SM        information) to the AMF. The N2 SM information includes the QFI,        User location Information and an indication that the QoS Flow is        released. The AMF invokes Nsmf_PDUSession_UpdateSMContext (N2 SM        information),    -   (AN initiated notification control) In case notification control        is configured for a GBR Flow, (R)AN sends a N2 message (PDU        Session ID, N2 SM information) to SMF when the (R)AN decides the        QoS targets of the QoS Flow cannot be fulfilled. The N2 SM        information includes the QFI indicating that the QoS targets for        that QoS flow cannot be fulfilled. The AMF invokes        Nsmf_PDUSession_UpdateSMContext (N2 SM information). If the PCF        has subscribed to the event, SMF reports this event to the PCF        for each PCC Rule for which notification control is set, see        step 2. Alternatively, if dynamic PCC does not apply for this        DNN, and dependent on locally configured policy, the SMF may        start SMF requested PDU Session Modification procedure, see step        3 b.

Step 2: The SMF may need to report some subscribed event to the PCF byperforming a Session Management Policy Modification procedure as definedin clause 4.16.5. The PCF may provide new policy information to the SMF.This step may be skipped if PDU Session Modification procedure istriggered by step 1 b or 1 d. If dynamic PCC is not deployed, the SMFmay apply local policy to decide whether to change the QoS profile.

Steps 3 to 7 are not invoked when the PDU Session Modification requiresonly action at an UPF (e.g. gating).

Step 3 a: For UE or AN initiated modification, the SMF responds to theAMF through Nsmf_PDUSession_UpdateSMContext (N2 SM information (PDUSession ID, QFI(s), QoS Profile(s), Session-AMBR), N1 SM container (PDUSession Modification Command (PDU Session ID, QoS rule(s), QoS ruleoperation. Session-AMBR))). See TS 23.501 [2] clause 5.7 for the QoSProfile and QoS rule.

-   -   The N2 SM information carries information that the AMF may        provide to the (R)AN. It may include the QoS profiles and the        corresponding QFIs to notify the (R)AN that one or more QoS        flows were added or modified. It may include only QFI(s) to        notify the (R)AN that one or more QoS flows were removed. If the        PDU Session Modification was triggered by the (R)AN Release in        step 1 d the N2 SM information carries an acknowledgement of the        (R)AN Release. If the PDU Session Modification was requested by        the UE for a PDU Session that has no established User Plane        resources, the N2 SM information provided to the (R)AN includes        information for establishment of User Plane resources.    -   The SMF may send the QVER Rule to the (R)AN in the N2 SM        information message.    -   The N1 SM container carries the PDU Session Modification Command        that the AMF may provide to the UE. It may include the QoS rules        and corresponding QoS rule operation to notify the UE that one        or more QoS rules were added, removed or modified.    -   The SMF may send the QVER Rule to the UE in the N1 SM container.

Step 3 b: For SMF requested modification, the SMF invokesNamf_Communication_N1N2MessageTransfer (N2 SM information (PDU SessionID, QFI(s), QoS Profile(s), Session-AMBR), N1 SM container (PDU SessionModification Command (PDU Session ID, QoS rule(s), QoS rule operation,Session-AMBR))),

The SMF may send the AVER Rule to the (R)AN in the N2 SM informationmessage. The SMF may send the QVER Rule to the UE in the N1 SMcontainer.

If the UE is in CM-IDLE state and an ATC is activated, the AMF updatesand stores the UE context based on theNamf_Communication_N1N2MessageTransfer and steps 4, 5, 6 and 7 areskipped. When the UE is reachable e.g. when the UE enters CM-CONNECTEDstate, the AMF forwards the N1 message to synchronize the UE contextwith the UE.

Step 4: The AMF may send N2 PDU Session Request (N2 SM informationreceived from SMF, NAS message (PDU Session ID, N1SM container (PDUSession Modification Command))) Message to the (R)AN.

Step 5: The (R)AN may issue AN specific signalling exchange with the UEthat is related with the information received from SMF. For example, incase of a 3GPP (R)AN, an RRC Connection Reconfiguration may take placewith the UE modifying the necessary (R)AN resources related to the PDUSession.

Step 6: The (R)AN may acknowledge N2 PDU Session Request by sending a N2PDU Session Ack (N2 SM information (List of accepted/rejected QFI(s), ANTunnel Info, PDU Session ID), User location Information) Message to theAMF. In case of Dual Connectivity, if one or more QFIs were added to thePDU Session, the Master (R)AN node may assign one or more of these QFIsto a (R)AN node which was not involved in the PDU Session earlier; Inthis case the AN Tunnel Info includes a new N3 tunnel endpoint for QFIsassigned to the new (R)AN node. Correspondingly, if one or more QFIswere removed from the PDU Session, a (R)AN node may not be involved inthe PDU Session anymore, and the corresponding tunnel endpoint isremoved from the AN Tunnel Info.

Step 7: The AMF forwards the N2 SM information and the User locationInformation received from the AN to the SMF viaNsmf_PDUSession_UpdateSMContext service operation. The SMF replies witha Nsmf_PDUSession_UpdateSMContext Response.

Step 8: The UE acknowledges the PDU Session Modification Command bysending a NAS message (PDU Session ID, N1 SM container (PDU SessionModification Command Ack)) message.

Step 9: The (R)AN forwards the NAS message to the AMF.

Step 10: The AMF forwards the N1SM container (PDU Session ModificationCommand Ack) and User Location Information received from the AN to theSMF via Nsmf_PDUSession_UpdateSMContext service operation. The SMFreplies with a Nsmf_PDUSession_UpdateSMContext Response.

Step 11: The SW may update N4 session of the UPF(s) that are involved bythe PDU Session Modification by sending N4 Session Modification Request(N4 Session ID) message to the UPF. For a PDU Session of Ethernet PDUType, the SMF may notify the UPF to add or remove Ethernet Packet FilterSet(s) and forwarding rule(s). If the timestamp is required for ingress(incoming) and/or egress (outgoing) PDU, the SMF provides an indicationto add the Timestamp to Ingress PDU and Timestamp to Egress PDU as oneof parameters to the UPF.

The SMF may send the QVER Rule to the UPF in the N4 Session ModificationRequest.

NOTE 2: The UPF that are impacted in the PDU Session Modificationprocedure depends on the modified QoS parameters and on the deployment.For example in case of the session AMBR of a PDU Session with an UL CLchanges, only the UL CL is involved,

Step 12: If the SMF interacted with the PCF in step 1 b or 2, the SMFnotifies the PCF whether the PCC decision could be enforced or not byperforming a Session Management Policy Modification procedure as definedin clause 4.16.5,

-   -   SMF notifies any entity that has subscribed to User Location        Information related with PDU Session change.        N4 Reporting Procedures

FIG. 12 illustrates a representative N4 reporting procedure used by theUPF to report events to the SMF.

This procedure is used by the UPF to report events related to an N4session for an individual PDU Session. The triggers for event reportingwere configured on the UPF during N4 Session Establishment/Modificationprocedures by the SMF.

Step 1: The UPF detects that an event has to be reported. The reportingtriggers include the following cases:

-   -   (1) Usage report.        -   Usage information may be collected in the UPF and reported            to the SMF as defined in clause 5.8 and clause 5.12 of TS            23.501 [2].    -   (2) Start of traffic detection.        -   When traffic detection is requested by SMF and the start of            traffic is detected for a Packet Detection Rule (PDR) as            described in clause 5.8 of TS 23.501 [2], the UPF may report            the start of traffic detection to the SMF and indicate the            corresponding PDR rule ID.    -   (3) Stop of traffic detection        -   When traffic detection is requested by SMF and the end of            traffic is detected for a PDR as described in clause 5.8 of            TS 23.501 [2], the UPF may report the stop of traffic            detection to the SMF and indicate the corresponding PDR rule            ID.    -   (4) Detection of 1st downlink data for UE in CM-IDLE state.        -   When UPF receives the downlink packet but no N3/N9 tunnel            for downlink data transmission exists and the buffering is            performed by the UPF, it may report the detection of 1st            downlink data to SMF for the purpose of downlink data            notification. The SPF may also report the DSCP of the packet            when instructed by SMF (e.g. in case the Paging Policy            Differentiation feature described in clause of 5.4.3 of TS            23.501 [2] is enabled at the UPF).    -   (5) Detection of QoS violated events to the SMF, The SMF may        configure the UPF how often the notification from UPF is        forwarded to the PCF: immediately, periodically, or event-based,        when the UP of PDU Session is deactivated, or when the PDU        Session is released.        -   the packet delay is larger than the UPF PDB;        -   the measured data burst volume within a period of UPF PDB is            larger than the Maximum Data Burst Volume; and        -   the measured flow bitrate within the Averaging Window is            larger than the MFBR;        -   the IMF cannot support the GFBR;        -   the measured Session-AMBR is larger than the authorized            Session-AMBR;        -   the measured UE-AMBR is larger than the subscribed UE-AMBR;        -   a PDU is dropped; and        -   a measured packet error rate (PER) is higher than the            maximum PER given in the QoS PCC.

The SMF may request the UPI; to add timestamp for packet delaymeasurements.

Step 2: The UPF sends an N4 report message (N4 Session ID, list of[Reporting trigger, Measurement information]) to the SMF.

The Reporting trigger parameter contains the name of the event whichtriggered the report and the Measurement information parameter containsthe actual information that the SMF requested to be informed about Step3: The SMF identifies the N4 session context based on the received N4Session ID and applies the reported information for the correspondingPDU Session. The SMF responds with an N4 report ACK message.

As described above, for QoS flows, such as delay critical GBR Flows, ifconfigured, the PCEF may send a notification message to the SMF toreport any of the following QoS violated events:

-   -   the packet delay is larger than the UPF PDB;    -   the measured data burst volume within a period of UPF PDB is        larger than the Maximum Data Burst Volume;    -   the measured flow bitrate within the Averaging Window is larger        than the MFBR;    -   the UPF cannot support the GFBR;    -   the measured Session-AMBR is larger than the authorized        Session-AMBR;    -   the measured UE-AMBR is larger than the subscribed UE-AMBR a PDU        is dropped; and

a measured packet error rate (PER) is higher than the maximum PER givenin the QoS PCC. According to the request from the SMF, the UPF or thePCEF of UPF may report packet delay measurement of individual PDU in theUL and/or DL of QoS flows, based on the timestamp(s) of received PDUs inthe UL sent from the LE and/or (RAN node. The UPF or the PCEF of UPF mayreport average packet delay of individual QoS flows, based on theindividual packet delay measurements in the UL and/or DL.

The notification message may include any one or more of a time stamp ofthe event, the name of the violated QoS parameter, and the value of themeasured violated parameter.

Policy and Charging Control Rule

To enable the enforcement in the 5GC of the policy decisions made by thePCF for the policy and charging control of a service data flow, the 5GCmay provide 5G Policy and Charging Control information from the PCF tothe SMF as described in table

The differences with table 6.3 in TS 23.203 [4] are shown, either “none”means that the IE applies in 5GS or “removed” meaning that the IE doesnot apply in 5G-S, this is due to the lack of support in the 5GS forthis feature or “modified” meaning that the IE applies with somemodifications defined in the IE.

TABLE 1 The PCC rule information in 5GC PCF permitted Differences tomodify for a compared Information dynamic PCC with table 6.3. nameDescription Category rule in the SMF in TS 23.203 [4] Rule UniquelyMandatory No None identifier identifies the PCC rule, within a PDUSession. It is used between PCF and SMF for referencing PCC rules.Service data This part defines flow the method for detection detectingpackets belonging to a service data flow. Precedence Determines theConditional Yes None order, in which (NOTE 2) the service data flowtemplates are applied at service data flow detection, enforcement andcharging. (NOTE 1). Service data For IP PDU Mandatory ConditionalModified flow traffic: Either (NOTE 3) (NOTE 4) (packet filters templatea list of for Ethernet service data PDU traffic flow filters or added)an application identifier that references the corresponding applicationdetection filter for the detection of the service data flow. ForEthernet PDU traffic: Combination of traffic patterns of the EthernetPDU traffic. It is defined in 3GPP TS 23.501 [2], clause 5.7.6.3 Mutefor Defines whether Conditional No None notification application's (NOTE5) start or stop notification is to be muted. Charging This part definesidentities and instructions for charging and accounting that is requiredfor an access point where flow based charging is configured Charging keyThe charging Yes None system (OCS or OFCS) uses the charging key todetermine the tariff to apply to the service data flow. Service Theidentity of Yes None identifier the service or service component theservice data flow in a rule relates to. Sponsor An identifier,Conditional Yes None Identifier provided from (NOTE 6) the AF whichidentifies the Sponsor, used for sponsored flows to correlatemeasurements from different users for accounting purposes. ApplicationAn identifier, Conditional Yes None Service provided from (NOTE 6)Provider the AF which Identifier identifies the Application ServiceProvider, used for sponsored flows to correlate measurements fromdifferent users for accounting purposes. Charging Indicates theConditional No None method required (NOTE 7) charging method for the PCCrule. Values: online, offline or neither. Measurement Indicates Yes Nonemethod whether the service data flow data volume, duration, combinedvolume/duration or event may be measured. This is applicable toreporting, if the charging method is online or offline. Note: Eventbased charging is only applicable to predefined PCC rules and PCC rulesused for application detection filter (i.e. with an applicationidentifier). Application An identifier, No None Function provided fromRecord the AF, Information correlating the measurement for the Chargingkey/Service identifier values in this PCC rule with application levelreports. Service Indicates that Yes None identifier separate usage levelreports may be reporting generated for this Service identifier. Values:mandated or not required Policy This part defines control how to applypolicy control for the service data flow. Gate status The gate statusYes None indicates whether the service data flow, detected by theservice data flow template, may pass (Gate is open) or may be discarded(Gate is closed). 5G QoS Identifier for the Conditional Yes Modifiedidentifier authorized QoS (corresponds parameters for to QCI in theservice TS 23.203 [4]) data flow. QoS Indicates whether Conditional YesAdded Notification notifications Control are requested (QNC) from 3GPP(R)AN when the GFBR can no longer (or again) be fulfilled for a QoS Flowduring the lifetime of the QoS Flow. QoS violated Indicates ConditionalYes Added event Report whether QoS violated events are requested fromCN. Frequency of Indicates how Conditional Yes Added QoS violated oftenthe QoS event Report violated event Report is sent by (R)AN and UPF:immediately, periodically, or event-based, when the UP of PDU Session isdeactivated, when the PDU Session is released, when the UE entersCM-IDLE state (for (R)AN), when UE enters RRC-INACTIVE state (for(R)AN). Reflective Indicates to apply Yes Added QoS reflective QoSControl for the SDF. UL-maximum The uplink Yes None bitrate maximumbitrate authorized for the service data flow DL-maximum The downlink YesNone bitrate maximum bitrate authorized for the service data flowUL-guaranteed The uplink Yes None bitrate guaranteed bitrate authorizedfor the service data flow DL-guaranteed The downlink Yes None bitrateguaranteed bitrate authorized for the service data flow UL sharingIndicates resource No None indication sharing in uplink direction withservice data flows having the same value in their PCC rule DL sharingIndicates resource No None indication sharing in downlink direction withservice data flows having the same value in their PCC rule RedirectRedirect state of Conditional Yes None the service data (NOTE 8) flow(enabled/ disabled) Redirect Controlled Conditional Yes None DestinationAddress (NOTE 9) to which the service data flow is redirected whenredirect is enabled ARP The Allocation Conditional Yes None andRetention (NOTE 10) Priority for the service data flow consisting of thepriority level, the pre-emption capability and the pre-emptionvulnerability Bind to QoS Indicates that the Conditional Yes ModifiedFlow dynamic PCC (NOTE 11) (corresponds associated rule may always tobind to the with the have its binding default bearer default QoS withthe QoS in TS 23.203 [4]) rule Flow associated with the default QoSrule. PS to CS Indicates whether Removed session the service datacontinuity flow is a candidate for vSRVCC. Access This part describesNetwork access network Information information to be Reporting reportedfor the PCC rule when the corresponding bearer is established, modifiedor terminated. User The serving cell Yes None Location of the UE is toReport be reported. When the corresponding bearer is deactivated, and ifavailable, information on when the UE was last known to be in thatlocation is also to be reported. UE The time zone Yes None Timezone ofthe UE is to Report be reported. Usage This part describes NoneMonitoring identities required Control for Usage Monitoring Control.Monitoring The PCF uses the Yes None key monitoring key to groupservices that share a common allowed usage. Indication of Indicates thatthe Yes None exclusion service data flow from session may be excludedlevel from PDU monitoring Session usage monitoring Traffic This partSteering describes Enforcement identities Control required for TrafficSteering Enforcement Control. Traffic Reference to a Yes None steeringpre-configured policy traffic steering identifier(s) policy at the SMF(NOTE 12). Data Identifier of the Yes Added Network target Data AccessNetwork Access. Identifier It is defined in 3GPP TS 23.501 [2], clause5.6.7. Data Indicates whether Yes Added Network a notification Access incase of change Change of DNAI at report addition/change/ removal of theUPF is requested, as well as the destination(s) for where to provide thenotification. The notification information includes the target DNAI andan indication of early and/or late notification. It is defined in 3GPPTS 23.501 [2], clause 5.6,7 NBIFOM This part describes related PCC rulecontrol information Information related with NBIFOM Allowed The accessto be Removed Access Type used for traffic identified by the PCC ruleRAN support This part defines information information supporting the(R)AN for e.g. handover threshold decision. UL The maximum ConditionalYes None Maximum rate for lost (NOTE 13) Packet Loss packets that canRate be tolerated in the uplink direction for the service data flow. Itis defined in TS 23.501 [2], clause 5.7.2.8. DL The maximum ConditionalYes None Maximum rate for lost (NOTE 13) Packet Loss packets that canRate be tolerated in the downlink direction for the service data flow.It is defined in TS 23.501 [2], clause 5.7.2.8. NOTE 1: For PCC rulesbased on an application detection filter, the precedence is onlyrelevant for the enforcement, i.e. when multiple PCC rules overlap, onlythe enforcement, reporting of application starts and stops, monitoring,and charging actions of the PCC rule with the highest precedence may beapplied. NOTE 2: The Precedence is mandatory for PCC rules with SDFtemplate containing SDF filter(s). For dynamic PCC rules with SDFtemplate containing an application identifier, the precedence is eitherpreconfigured in SMF or provided in the PCC rule from PCF. NOTE 3:Either service data flow filter(s) or application identifier may bedefined per each rule. NOTE 4: YES, in case the service data flowtemplate consists of a set of service data flow filters. NO in case theservice data flow template consists of an application identifier NOTE 5:Optional and applicable only if application identifier exists within therule. NOTE 6: Applicable to sponsored data connectivity. NOTE 7:Mandatory if there is no default charging method for the PDU Session.NOTE 8: Optional and applicable only if application identifier existswithin the rule. NOTE 9: If Redirect is enabled. NOTE 10: Mandatory whenpolicy control on SDF level applies. NOTE 11: The presence of thisattribute causes the 5QI/ARP/QNC of the rule to be ignored. NOTE 12: TheTraffic steering policy identifier can be different for uplink anddownlink direction. If two Traffic steering policy identifiers areprovided, then one is for uplink direction, while the other one is fordownlink direction. NOTE 13: Optional and applicable only for voiceservice data flow in this release.

The QoS violated event Report policy may include the list of QoSviolated events, or the list of QoS parameters to be monitored andviolated reported.

The QoS violated event Report may include timestamp of the event, NFtype (e.g. (R)AN or UPF ID) (e.g. IP Address, FQDN), UE ID (e.g. SUPI,GPSI), PDU Session ID, QFI, the name of violated QoS parameter, and themeasured value of violated QoS parameter. If the packet delay is largerthan the PDB, the QoS violated event Report may include the packet size.

Event Exposure Using NEF

Monitoring Events

The Monitoring Events feature is intended for monitoring of specificevents in 3GPP system and making such monitoring events informationreported via the NEF. It is comprised of means that allow NFs in 5GS forconfiguring the specific events, the event detection, and the eventreporting to the requested party.

To support monitoring features in roaming scenarios, a roaming agreementneeds to be made between the HPLMN and the VPLMN. The set ofcapabilities required for monitoring may be accessible via NEF to NFs in5GS. Monitoring Events via the UDM and the AMF enables NEF to configurea given Monitor Event at UDM or AMF, and reporting of the event via UDMand/or AMF. Depending on the specific monitoring event or information,it is either the AMF or the UDM that is aware of the monitoring event orinformation and makes it reported via the NEF.

The following table illustrates the monitoring events:

TABLE 3 List of event for monitoring capability Which NF detects EventDescription the event Loss of Network detects that the UE is no longerAMF Connec- reachable for either signalling or user plane tivitycommunication. UE It indicates when the UE becomes reachable AMFreachability for sending either SMS or downlink data to UDM: the UE,which is detected when the UE reachability transitions to CONNECTED modeor when for SMS the UE will become reachable for paging, e.g., PeriodicRegistration Update timer. Location It indicates either the CurrentLocation or the AMF Reporting Last Known Location of a UE. One-time andContinuous Location Reporting are supported for the Current Location.For Continuous Location Reporting the serving node(s) sends anotification every time it becomes aware of a location change, with thegranularity depending on the accepted accuracy of location. (see NOTE 1)For One-time Reporting is supported only for the Last Known Location.Change of It indicates a change of the ME's PEI UDM SUPI-PEI (IMEI(SV))that uses a specific subscription association (SUPI) Roaming Itindicates UE's current roaming status UDM status (the serving PLMNand/or whether the UE is in its HPLMN) and notification when that statuschanges. (see NOTE 2) Commu- It is identified by (R)AN/NAS release codeAMF nication failure Availability It indicates when there has been someAMF after DNN data delivery failure followed by the failure UE becomingreachable. Number It indicates the number of UEs that AMF of UEs are inthe geographic area present described by the AF. The AF in a may ask forthe UEs that the system knows by geo- its normal operation to be withinthe area graphical (Last Known Location) or the AF may request area thesystem to also actively look for the UEs within the area (CurrentLocation). QoS Indicates the QoS violated events as described SMFviolated above event Report NOTE 1: Location granularity for eventrequest, or event report, or both could be at cell level (Cell ID), TAlevel or other formats e.g. shapes (e.g. polygons, circles, etc.) orcivic addresses (e.g. streets, districts, etc.) which can be mapped byNEF. NOTE 2: Roaming status means whether the UE is in HPLMN or VPLMN.

The QoS violated event report policy may include the list of QoSviolated events, of the QoS parameters to be reported, such as packetdelay, packet error rate, maximum data. burst volume.

The QoS violated event Report may include a timestamp of the event, UEID (e.g. SUPI, GPSI), PDU Session ID, QFI, the name of violated QoSparameter, and the measured value of violated QoS parameter. If thepacket delay is larger than the PDB, the QoS violated event Report mayinclude the packet size.

In the embodiments above, the UPF and (R)AN may receive instructionsfrom the PCC rules from the PCF via SMF to add timestamp to the N3 andN9 tunnel header. In another embodiment, the timestamp can be added tothe outer IP header. The UPF or (R)AN node send an instruction or anindication to the IP layer to add timestamp to the IP header, thetimestamp can be inserted in the extension header field of the IPheader. The instruction from the UPF or (R)AN can be an explicitinstruction, or implicit instruction that is carried in one or more DSCPoptions that could trigger the IP router to add timestamp in the IPextension header. The timestamp option may be stored in the UE Contextin the (R)AN or UPF.

The packets of QoS flows may be sent over two UP paths to improve thereliability. This method is called redundant packet transmission, inwhich the likelihood of QoS degradation will be reduced significantly.For example the packets of delay critical QoS flows, or QoS flows ofURLLC applications, are often sent between a data source, such as anapplication server, and the UE over two data paths. The two data pathsmay be established between the application server and the UE, or betweenthe PSA UPF and the UE, or between the PSA UPF and the (R)AN node, orbetween the (R)AN and the UE. The CP functions in the CN may be aware orestablish the two transmission paths. The presented methods to monitorthe QoS parameters, measuring the QoS parameters, reporting the QoSparameters, reporting QoS violated events can be applied to one of thetwo UP paths, or both UP paths. Since there are two UP paths, thereporting of QoS flows may be different for different packet redundanttransmission scenarios.

The PCF may send the QoS monitoring and QoS reporting policy to the SMF,which may indicate which type of (radio) access technology ((R)AT), suchas 3GPP RAT and non-3GPP RAT, to be monitored. The SMF may decide tomonitor and report QoS parameters for one UP path or both UP paths.

If the two UP paths are established between the data source and the UE,the AF may request the CN to monitor and report QoS parameters, and/orQoS violation events of the two UP paths. The PCF or SMF may receive therequests of the AF to monitor the two UP paths. The AF may includeinformation to identify the two UP paths, such as IP addresses of theQoS flows or IP addresses of the PDU sessions that send PDU over the twoUP paths. The AF may include an indication that the two PDU sessions ortwo QoS flows serve the same data transaction of the UE. The two PDUSessions or two QoS flows that serve the same data transaction may beserve by the same set of mobile network functions (such as the same AMF,the same PCF, the same SMF, the same UDM, the same UPF, the same (R)ANnode), or different mobile network functions (such as different AMFs,and/or different PCFs, and/or different SMFs, and/or different UDMs,and/or different UPFs, and/or different (R)AN nodes). In any cases, thePCF(s) may send request(s) to the SMF(s) to monitor and report QoSparameters as presented early.

The PCF(s) may send response or notification to the AF that carry themeasured QoS parameters, and/or QoS violated events. The UPF or (R)ANmay report the UL and/or DL QoS parameters of one UP path, or two UPpaths.

The (R)AN or UPF may select the best measured QoS parameters to reportor notify the SMF. For example the UPF may report the smallest packetdelay of the two UP paths, in the UL and/or DL, to the SMF.

In case the two UP paths are established between the PSA UPF and the UE,the same PCF and SMF may serve the PDU session. The PCF may request theSMF to monitor and report QoS performance of one or both UP paths. Incase the QoS parameters of the two UPF paths are monitored and reported,the UPF may report a combined QoS parameters for the two UP paths. Forexample, for the packet delay monitoring, the UPF sends DL PDUs to the(R)AN(s) with time stamps, the (R)AN(s) may send message(s) over the N3UL interface(s) to the UPF to report the PDU delay for the same PDU. The(R)AN may include the sequence number of the PDU, which is part ofheader of GIP-U protocol so that the SMF knows the packet delay reportedfor which previously sent PDU in the DL. in the UL, the (R)AN(s) mayinclude the time stamp(s), which may indicate when the PDU was sent fromthe UE, and/or when the PDU is sent from the (R)AN node. When the UPFreceives the UL PDU with time stamps, the UPF may combine the timestamps of the UL PDU to determine the UL packet delay, which is thesmallest packet delay of the two UL paths. When the UPF receives the DLpacket delay reports from the one or two (R)AN nodes, the UPF maydetermine the DL packet delay, which is the smallest packet delay of thetwo DL paths. The UPF may notify the SMF the packet delay of the UL,which is the smallest packet delay of the two UL paths. The UPF maynotify the SMF the packet delay of the DL, which is the smallest packetdelay of the two DL paths. The (R)AN(s) may also send the DL packetdelay of the two DL UP paths to the SMF over the N2. interface.Alternatively, the (R)AN may select the smallest packet delay of the twoDL paths as the packet delay of the PDU and send the packet delay to theSMF over the N2 interface,

In case the (R)AN establishes two data paths between the (R)AN node andthe UE, and there is one UP path between the (R)AN node and the PSA UT,the (R)AN may perform the packet delay measurements in the UL and DL forthe two data paths between the (R)AN node and the UE. The (R)AN mayselect the smallest packet delay of the two data paths over the airinterface as the packet delay over the air interface, for the UL and DL.The (R)AN may send the packet delay of the UL and DL to the UPF over theN3 UL interface, or to the SMF over the N2 SM interface.

In case there are two UP paths between the (R)AN node and the PSA UPF,the UPF may send a DL PDU to the two UP paths. The DL time stampindicating the time the PDU arrived the UPF may be added to the DL N3interface (or N9 interface in case an I-UPF is used) tunnel header ofone or two UP paths that deliver DL PDU and require packet delaymonitoring. The (R)AN node may send UL PDU to the two UP paths. The ULtime stamp indicating the time the PDU arrived the (R)AN and/or timestamp indicating packet delay of the air interface, in the UL and/or DL,may be added to the UL N3 or N9 tunnel header of one or two UP pathsthat deliver UL PDU and require packet delay monitoring. The (R)AN nodemay also send DL packet delay of the monitored DL UP path(s) in the ULN3 or N9 interface that paired with the DL UP path. The (R)AN node mayalso send the packet delay of the two DL UP paths in one of the UL N3interface (or N9 interface in case an I-UPF is used).

The (R)AN may send a message in the N3 UL interface towards the PSA UPFto inform the PSA UPF about the packet delay in the downlink and uplink.This message may carry one or more of following packet delayinformation: This message may carry one or more of following packetdelay information: one or more indication to identify the PDU such assequence number(s) of UL and/or DL PDU carried in the UL and/or DL N3 orN9 tunnel header, a copy of DL a copy of UL PDU, one or more time stampindicating the time(s) the UL and/or DL PDU arrived at a UP entity, oneor more time stamp indicating the time(s) the UL and/or DL PDU left a UPentity, one or more packet delay value indicating the packet delay of DLand/or UL PDU transferred between two LT entities, one or more packetdelay value indicating the measured packet processing delay of DL and/orUL PDU in a UP entity, one or more packet delay measurement resultindicating the measured packet delay of a network segment between anytwo UP entities was less than or equal to the assigned packet delaybudget for this network segment, one or more packet delay measurementresult indicating the measured packet delay of a network segment betweentwo LT entities was greater than the assigned packet delay budget forthis network segment. The UP entity could be one or more of followingnetwork entity: the PSA UPF, I-UPF, (R)AN node, and UE. In the packetdelay report, the order of the time stamps, or the order of packetprocessing delay is the same as the order of the time stamps carried inthe UL and/or DL tunnel header that carries the PDU so that the PSA UPFcould map the packet delay report to the packet delay of networksegments and/or the packet processing delay in each UP entity. Themessage may also explicitly carry the indication of network segment, forexample CN segment, (R)AN segment, UP entity identifier and name,corresponding to the packet delay information. The (R)AN may send thesame packet delay information to the SMF in the N2 interface towards theSMF serving the PDU Session.

PSA UPF may receive the packet delay information from the (R)AN andI-UPF(s), the PSA UPF uses this packet delay information to calculatethe packet delay in DL and/or UL of the network segment between the PSAUPF and an I-UPF, between an I-UPF and another I-UPF, between an I-UPFand the (R)AN, between the PSA UPF and the PSA LAT and the (R)AN,between the (R)AN and the UE.

The PSA UPF may send a message towards the SMF, for example over the N2interface, to inform or report the SMF about the packet delayinformation in the DL and UL. This message may carry one or more offollowing packet delay information: one or more indication to identifythe PDU such as sequence number(s) of UL and/or DL PDU carried in the ULand/or DL N3 or N9 tunnel header, a copy of DL PDU, a copy of UL PDU,one or more time stamp indicating the time(s) the UL and/or DL PDUarrived at a UP entity, one or more time stamp indicating the time(s)the UL and/or DL PDU left a UP entity, one or more packet delay valueindicating the packet delay of DL and/or UL PDU transferred between twoUP entities, one or more packet delay value indicating the measuredpacket processing delay of DL and/or UL PDU in a UP entity, one or morepacket delay measurement result indicating the measured packet delay ofa network segment between any two UP entities was less than or equal tothe assigned packet delay budget for this network segment, one or morepacket delay measurement result indicating the measured packet delay ofa network segment between two UP entities was greater than the assignedpacket delay budget for this network segment. The UP entity could be oneor more of following network entity: the PSA UPF, I-UPF, (R)AN node, andUE. In the packet delay report, the order of the time stamps, or theorder of packet processing delay is the same as the order of the timestamps carried in the UL and/or DL tunnel header that carries the PDU sothat the SMF could map the packet delay report to the packet delay ofnetwork segments and/or the packet processing delay in each UP entity.The message may also explicitly carry the indication of network segment,for example CN segment, (R)AN segment, UP ID, corresponding to thepacket delay information.

The SMF may receive the packet delay information report from the (R)ANand/or the UPF. The SMF may calculate one or more of the followingpacket delay information: the packet delay between two UP entities, thepacket processing delay of a UP entity, the packet delay of networksegment such as CN and/or (R)AN segment, for the DL and UL.

If one or more of network function, such PCF, NWDAF, AF, requested orsubscribed to receive packet delay information, the SMF may send to thisNF the packet delay information received from the (R) AN and/or the UPF.The SMF may send to the requesting or subscribing NT one or more offollowing packet delay information: the calculated packet delay betweentwo UP entities and identifiers of these two UP entities, the identifierof the UP entity and packet processing delay of this UP entity, thepacket delay of network segment such as CN and/or (R)AN and/or wholenetwork (between the PSA UPF and UE), for the DL and/or UL, one or moreindication that the measured packet delay in a network segment is notgreater than the PDB assigned to this network segment for the UL and/orDL, one or more indication that the measured packet delay in a networksegment is greater than the PDB assigned to this network segment for theUL and/or DL.

In some embodiments, the AF may request or subscribe the PCF or SMF toreceive notification for packet delay violated events. In this case, PCFmay create QVER policy that requests the PSA UPF and/or (R)AN and/or UEto report the time stamp(s) indicating the time the PDU arrives orleaves a UP entity. The UP entity could be one or more of PSA UPF,(R)AN, and UE. Alternatively, the PCF may create QVER policy thatrequests the PSA UPF and/or (R)AN to report the end-to-end packet delaybetween the PSA UPF and UE, in the UL and/or DL, The PCF may create QVERpolicy and send to the SMF. The SMF sends the QVER policy to the UPentity, such as PSA UPF, I-UPF, (R)AN, UE. The UP entity follows theQVER policy and reports the packet delay information to the SMF. The SMFmay send the packet delay information to the PCF and/or NWDAF. Based onthe packet delay information received from the (R)AN and/or the PSA UPF,and/or the UE, the PCF or SMF may determine whether the DL and/or ULpacket delay in the mobile network meets the PDB requirement or not. ThePCF or SMF may only send the packet delay violation event notificationto the AF when the end-to-end packet delay between the PSA UPF and theUE, in the UL and/or DL, is greater than the end-to-end PDB assigned forpacket transferred between the PSA UPF and UE, in the DL and/or UL. Thismethod may help to reduce a large number of signaling messages from theCN to the AF just to inform the AF that the packet delay in the mobilenetwork meets the PDB requirement, while the details of packet delayinformation is still reported from the UP entity to the CP function(s)for further processing and/or data analytics.

In some embodiments, the AF may request or subscribe the PCF or SMF toreceive notification for packet delay violated events. The AF mayinclude in the request a packet delay threshold. The packet delaythreshold may be greater, or equal, or larger than the end-to-end PDB. Apacket delay violated event happens when the packet delay in thenetwork, e.g. the packet delay between the PSA UPF and UE, is greaterthan the packet delay threshold. The mobile network may notify the AFpacket delay violated events. In this case, the SMF may receive thepacket delay reports, for example from the (R)AN and/or UP, for PDUtransmission in the network. If the AF requests or subscribes to receivenotification of the packet delay which is larger than the packet delaythreshold, the SMF may send a notification to the AF, which may includethe information described in the present document, including one or moreof the value of packet delay, an indication of packet delay violatedevent indicating the packet delay was greater than the packet delaythreshold, the time stamp, a copy of the packet, the UE location(indicated by for example the (R)AN ID, cell ID, geographical location,tracking area, registration area).

In another embodiment, the AF may request or subscribe the PCF or SMF toreceive notification for packet delay violated events. The AF mayinclude in the request one or more of following information: packetdelay threshold, the time window to calculate the average packet delay.The packet delay threshold may be greater, or equal, or larger than theend-to-end PDB. if the time window is included in the message sent fromthe AF, the SMF may use this time window to calculate the average packetdelay, in which the average packet delay of multiple packets reportedwithin the time window is calculated. A packet delay violated eventhappens when the average packet delay in the network, e.g. the averagepacket delay between the PSA UPF and UE, is greater than the packetdelay threshold. The mobile network may notify the AF packet delayviolated events. In this case, the SMF may receive the packet delayreports, for example from the (R)AN and/or UP, for PDU transmission inthe network. If the AF requests or subscribes to receive notification ofthe packet delay which is larger than the packet delay threshold, theSMF may send a notification to the AF, which may include the informationdescribed in the present document, including one or more of the value ofpacket delay, an indication of packet delay violated event indicatingthe packet delay was greater than the packet delay threshold, the timestamp, a copy of the packet, the UE location (indicated by for examplethe (R)AN ID, cell ID, geographical location, tracking area,registration area).

Although the present invention has been described with reference tospecific features and embodiments thereof, it is evident that variousmodifications and combinations can be made thereto without departingfrom the invention. The specification and drawings are, accordingly, tobe regarded simply as an illustration of the invention as defined by theappended claims, and are contemplated to cover any and allmodifications, variations, combinations or equivalents that fall withinthe scope of the present invention.

I claim:
 1. A method comprising: receiving, by a session managementfunction (SMF) from a policy control function (PCF), a policy associatedwith an application function (AF) request, wherein the policy indicatesthe SMF to report a packet delay; according to the policy, requesting bythe SMF, an access network (AN) node to report a packet delay betweenthe AN node and a user equipment (UE), and a user plane function (UPF)to report a packet delay between the AN node and the UPF; receiving, bythe SMF, one or more indications of the packet delay between the AN nodeand the UE and the packet delay between the AN node and the UPF; andsending, by the SMF to the AF, a report associated with both the packetdelay between the AN node and the UE and the packet delay between the ANnode and the UPF.
 2. The method according to claim 1, wherein the reportis sent from the SMF to the AF without involving the PCF, wherein thepolicy further indicates the SMF to report the packet delay to the AF.3. The method according to claim 1, wherein the report is sent from theSMF to the PCF which is configured to send the report to the AF, whereinthe policy further indicates the SMF to report the packet delay to thePCF.
 4. The method according to claim 1, wherein the packet delay to bereported as the policy indicated is an end-to-end packet delay.
 5. Themethod according to claim 4, wherein the packet delay includes one ormore of: an uplink packet delay and a downlink packet delay.
 6. Themethod according to claim 4, wherein the policy further indicates howoften to report the packet delay, and the SMF sends the report accordingto the policy.
 7. The method according to claim 4, wherein the policyfurther indicates to periodically report the packet delay, and the SMFsends the report periodically.
 8. The method according to claim 4,wherein the policy further indicates to report the packet delay when thepacket delay exceeds a threshold, and the SMF sends the report when thepacket delay exceeds the threshold.
 9. The method according to claim 4,wherein the policy further indicates to report the packet delay when thePDU session is released, and the SMF sends the report when the PDUsession is released.
 10. The method according to claim 4, wherein thereport includes the end-to-end packet delay, wherein the end-to-endpacket delay is a calculation result of the packet delay between the ANnode and the UE and the packet delay between the AN node and the UPF.11. The method according to claim 1, wherein the AF request is a requestfor a subscription to a packet delay report.
 12. A method comprising:receiving, by a policy control function (PCF) from an applicationfunction (AF), a request for a subscription to a packet delay report;and sending, by the PCF to a session management function (SMF), a policyassociated with the request, wherein the policy indicates the SMF toreport a packet delay and how often to report the packet delay.
 13. Themethod according to claim 12, wherein the method further comprises:receiving, by the PCF from the SMF, a report associated with both apacket delay between an access network (AN) node and a user equipment(UE) and a packet delay between the AN node and a user plane function(UPF); and sending, by the PCF to the AF, the report.
 14. The methodaccording to claim 12, wherein the policy further indicates the SMF toreport the packet delay to one of the PCF and an application function(AF).
 15. The method according to claim 12, wherein the packet delay tobe reported as indicated is an end-to-end packet delay.
 16. The methodaccording to claim 12, wherein the packet delay includes one or more of:an uplink packet delay and a downlink packet delay.
 17. The methodaccording to claim 12, wherein the policy further indicates toperiodically report the packet delay.
 18. The method according to claim12, wherein the policy further indicates to report the packet delay whenthe packet delay exceeds a threshold.
 19. The method according to claim12, wherein the policy further indicates to report the packet delay whenthe PDU session is released.
 20. The method according to claim 12,wherein the policy is sent by the PCF during a procedure of PDU sessionestablishment.
 21. The method according to claim 12, wherein the policyis sent by the PCF during a modification procedure associated with aprotocol data unit (PDU) session.
 22. An apparatus comprising one ormore processors coupled with a non-transitory computer-readable mediastoring instructions, that when executed by the one or more processors,cause the one or more processors to perform a method including:receiving, from a policy control function (PCF), a policy associatedwith an application function (AF) request, wherein the policy indicatesthe apparatus to report a packet delay; according to the policy,requesting an access network (AN) node to report a packet delay betweenthe AN node and a user equipment (UE); according to the policy,requesting a user plane function (UPF) to report a packet delay betweenthe AN node and the UPF; receiving one or more indications of the packetdelay between the AN node and the UE and the packet delay between the ANnode and the UPF; and sending to the AF a report associated with boththe packet delay between the AN node and the UE and the packet delaybetween the AN node and the UPF.
 23. An apparatus comprising one or moreprocessors coupled with a non-transitory computer-readable media storinginstructions, that when executed by the one or more processors, causethe one or more processors to perform a method including: receiving,from an application function (AF), a request for a subscription to apacket delay report; and sending to a session management function (SMF)a policy associated with the request, wherein the policy indicates theSMF to report a packet delay and how often to report the packet delay.24. A non-transitory computer-readable media storing instructions, thatwhen executed by one or more processors, cause the one or moreprocessors to perform a method including: receiving, from a policycontrol function (PCF), a policy associated with an application function(AF) request, wherein the policy indicates an apparatus associated withthe one or more processors to report a packet delay; according to thepolicy, requesting an access network (AN) node to report a packet delaybetween the AN node and a user equipment (UE); according to the policy,requesting a user plane function (UPF) to report a packet delay betweenthe AN node and the UPF; receiving one or more indications of the packetdelay between the AN node and the UE and the packet delay between the ANnode and the UPF; and sending to the AF a report associated with boththe packet delay between the AN node and the UE and the packet delaybetween the AN node and the UPF.
 25. A non-transitory computer-readablemedia storing instructions, that when executed by one or moreprocessors, cause the one or more processors to perform a methodincluding: receiving, from an application function (AF), a request for asubscription to a packet delay report; and sending to a sessionmanagement function (SMF) a policy associated with the request, whereinthe policy indicates the SMF to report a packet delay and how often toreport the packet delay.